This application claims priority to U.S. Ser. No. 61/181,515, filed May 27, 2009; which is commonly assigned and hereby incorporated by reference.
The present invention relates generally to lighting techniques. More specifically, embodiments of the invention include techniques for fabricating an improved optical device with improved electrostatic discharge characteristics fabricated on bulk semipolar or nonpolar crystalline semiconductor materials. Merely by way of example, the invention can be applied to applications such as white lighting, multi-colored lighting, general illumination, decorative lighting, automotive and aircraft lamps, street lights, lighting for plant growth, indicator lights, lighting for flat panel displays, other optoelectronic devices, and the like.
In the late 1800's, Thomas Edison invented the light bulb. The conventional light bulb, commonly called the “Edison bulb,” has been used for over one hundred years. The conventional light bulb uses a tungsten filament enclosed in a glass bulb sealed in a base, which is screwed into a socket. The socket is coupled to an AC power or DC power source. The conventional light bulb can be found commonly in houses, buildings, and outdoor lightings, and other areas requiring light. Unfortunately, drawbacks exist with the conventional Edison light bulb. That is, the conventional light bulb dissipates much thermal energy. More than 90% of the energy used for the conventional light bulb dissipates as thermal energy. Additionally, the conventional light bulb routinely fails often due to thermal expansion and contraction of the filament element.
To overcome some of the drawbacks of the conventional light bulb, fluorescent lighting has been developed. Fluorescent lighting uses an optically clear tube structure filled with a halogen gas and, which typically also contains mercury. A pair of electrodes is coupled between the halogen gas and couples to an alternating power source through a ballast. Once the gas has been excited, it discharges to emit light. Typically, the optically clear tube is coated with phosphors, which are excited by the light. Many building structures use fluorescent lighting and, more recently, fluorescent lighting has been fitted onto a base structure, which couples into a standard socket.
Solid state lighting techniques have also been used. Solid state lighting relies upon semiconductor materials to produce light emitting diodes, commonly called LEDs. At first, red LEDs were demonstrated and introduced into commerce. Red LEDs use Aluminum Indium Gallium Phosphide or AlInGaP semiconductor materials. Most recently, Shuji Nakamura pioneered the use of InGaN materials to produce LEDs emitting light in the blue color range for blue LEDs. The blue colored LEDs led to innovations such as solid state white lighting, the blue laser diode, which in turn enabled the BlueRay™ DVD player, and other developments. Other colored LEDs have also been proposed.
High intensity UV, blue, and green LEDs based on GaN have been proposed and even demonstrated with some success. Efficiencies have typically been highest in the UV-violet, dropping off as the emission wavelength increases to blue or green. Unfortunately, achieving high intensity, high-efficiency GaN-based green LEDs has been particularly problematic. The performance of optoelectronic devices fabricated on conventional c-plane GaN suffer from strong internal polarization fields, which spatially separate the electron and hole wave functions and lead to poor radiative recombination efficiency. Since this phenomenon becomes more pronounced in InGaN layers with increased indium content for increased wavelength emission, extending the performance of UV or blue GaN-based LEDs to the blue-green or green regime has been difficult. Furthermore, since increased indium content films often require reduced growth temperature, the crystal quality of the InGaN films is degraded. The difficulty of achieving a high intensity green LED has lead scientists and engineers to the term “green gap” to describe the unavailability of such green LED. In addition, the light emission efficiency of typical GaN-based LEDs drops off significantly at higher current densities, as are required for general illumination applications, a phenomenon known as “roll-over.” Other limitations with blue LEDs using c-plane GaN exist. These limitations include poor yields, low efficiencies, and reliability issues. Although highly successful, solid state lighting techniques must be improved for full exploitation of their potential. These and other limitations may be described throughout the present specification and more particularly below.
From the above, it is seen that techniques for improving optical devices is highly desired.
According to the present invention, techniques for lighting are provided. More specifically, embodiments of the invention include techniques for fabricating an improved optical device with electrostatic discharge characteristics fabricated on bulk semipolar or nonpolar materials. Merely by way of example, the invention can be applied to applications such as optoelectronic devices, and the like. Other applications that desire polarized emission include liquid crystal display (“LCD”) backlighting, liquid crystal on silicon (“LCOS”) lighting, selected applications of home and/or building lighting, medical applications, biological sampling, plant and algae growth, biofuels, microscopes, film and video (e.g., amusement, action, nature, in-door), multi-dimensional display or televisions, micro and/or pico displays, health and wellness, optical and/or data transmission/communication, security and safety, and others.
In a specific embodiment, the present invention the present invention provides a light emitting diode device, commonly called an LED, e.g., single LED device, array of LEDs. The device has a gallium nitride (GaN) substrate structure, which includes a surface region. The device also has an epitaxial layer overlying the surface region and a p-n junction formed within a portion of the epitaxial layer. In a preferred embodiment, the device also has one or more plane or line defects spatially configured in a manner to be free from intersecting the p-n junction. In a specific embodiment, the one or more plane or line defects are present at a surface defect density of 1×106 cm−2.
Benefits are achieved over pre-existing techniques using the present invention. In particular, the present invention uses either a non-polar or semipolar material, which has improved characteristics. In a specific embodiment, the present method and device using non-polar materials reduces polarization fields, which lead to reduced efficiency and gain. That is, the device has improved efficiency and gain as compared to conventional laser devices made of gallium containing materials made on conventional m-plane technology. In a preferred embodiment, the resulting device is smaller in size and has the capability of achieving power of large conventional devices. In a specific embodiment, the device has improved electro-static discharge characteristics. Depending upon the embodiment, the present apparatus and method can be manufactured using conventional materials and/or methods according to one of ordinary skill in the art. Depending upon the embodiment, one or more of these benefits may be achieved. These and other benefits may be described throughout the present specification and more particularly below.
The present invention achieves these benefits and others in the context of known process technology. However, a further understanding of the nature and advantages of the present invention may be realized by reference to the latter portions of the specification and attached drawings.
According to the present invention, techniques for lighting are provided. More specifically, embodiments of the invention include techniques for fabricating an improved optical device with electrostatic discharge characteristics fabricated on bulk semipolar or nonpolar materials. Merely by way of example, the invention can be applied to applications such as white lighting, multi-colored lighting, general illumination, decorative lighting, automotive and aircraft lamps, street lights, lighting for plant growth, indicator lights, lighting for flat panel displays, other optoelectronic devices, and the like.
While conventional optical devices have been fabricated on the c-plane of GaN substrates, researchers are exploring the properties of optical devices fabricated on m-plane GaN substrates. Specifically, c-plane bulk GaN is polar, while m-plane bulk GaN is non-polar along the growth direction. LEDs fabricated on the m-plane of bulk GaN substrates can emit highly polarized light. By utilizing non-polar GaN substrate-based LEDs in applications which require polarized light (such as LCD back-lighting), improved system efficiencies can therefore be achieved. Furthermore, optical devices are also fabricated from GaN substrates wherein the largest area surface is angled from the polar c-plane leading to semi-polar bulk GaN substrates. LEDs fabricated on bulk semi-polar GaN substrates can also emit partially polarized light according to other embodiments. The degree of polarization of the emission can be related to the crystallographic orientation of the largest surface area of the bulk GaN substrate, the composition and constitution of the individual layers that make up the LED structure, the electrical current density at which the polarization ratio is measured, how the measurement occurs, among other factors. Regarding the measurement, complex equipment including selected polarizers, photodetectors, and handling techniques are often required to determine the degree of polarization. The use of non-polar or semi-polar GaN in the fabrication of LEDs allows for the creation of optical devices that produce light of various levels of polarization
In order to increase the performance characteristics and reliability of devices fabricated using LEDs fabricated on bulk GaN substrates, it is necessary to improve the electrostatic discharge (ESD) characteristics of such LEDs. Specifically, improving the electrostatic discharge characteristics increases the breakdown voltage of the LED device allowing it to operate at the high currents generated by electro-static discharge. This in turn, leads to reduced device failure frequency and improved reliability. Such improved reliability is extremely noticeable in devices that use multiple arrays of LEDs such as display devices.
The substrate may have a large-surface orientation within ten degrees, within five degrees, within two degrees, within one degree, within 0.5 degree, or within 0.2 degree of (0 0 0 1), (0 0 0 −1), {1 −1 0 0}, {1 1 −2 0}, {1 −1 0 ±1}, {1 −1 0 ±2}, {1 −1 0 ±3}, or {1 1 −2 ±2}. The substrate may have a dislocation density below 104 cm−2, below 103 cm−2, or below 102 cm−2. The nitride base crystal or wafer may have an optical absorption coefficient below 100 cm−1, below 50 cm−1 or below 5 cm−1 at wavelengths between about 465 nm and about 700 nm. The nitride base crystal may have an optical absorption coefficient below 100 cm−1, below 50 cm−1 or below 5 cm−1 at wavelengths between about 700 nm and about 3077 nm and at wavelengths between about 3333 nm and about 6667 nm.
In one or more embodiments, the device can be configured with an optional release layer. The release layer comprises heavily cobalt-doped GaN, has a high crystal quality, and is substantially black, with an optical absorption coefficient greater than 1000 cm−1 or greater than 5000 cm−1 across the visible spectrum, including the range between about 465 nm and about 700 nm. The release layer is between about 0.05 micron and about 50 microns thick and has a temperature stability approximately the same as the underlying base crystal and exhibits minimal strain with respect to the underlying base crystal.
An n-type AluInvGa1-u-vN layer, where 0≦u, v, u+v≦1, is deposited on the substrate. The carrier concentration may lie in the range between about 1017 cm−3 and 1020 cm−3. The deposition may be performed using metal organic chemical vapor deposition (MOCVD) or molecular beam epitaxy (MBE).
Following deposition of the n-type AluInvGa1-u-vN layer for a predetermined period of time, so as to achieve a predetermined thickness, an active layer is deposited. The active layer may comprise a single quantum well or a multiple quantum well, with 2-10 quantum wells. The quantum wells may comprise InGaN wells and GaN barrier layers. In other embodiments, the well layers and barrier layers comprise AlwInxGa1-w-xN and AlyInzGa1-y-zN, respectively, where 0≦w, x, y, z, w+x, y+z≦1, where w<u, y and/or x>v, z so that the bandgap of the well layer(s) is less than that of the barrier layer(s) and the n-type layer. The well layers and barrier layers may each have a thickness between about 1 nm and about 20 nm. In another embodiment, the active layer comprises a double heterostructure, with an InGaN or AlwInxGa1-w-xN layer about 20 nm to about 500 nm thick surrounded by GaN or AlyInzGa1-y-zN layers, where w<u, y and/or x>v, z. The composition and structure of the active layer are chosen to provide light emission at a preselected wavelength. The active layer may be left undoped (or unintentionally doped) or may be doped n-type or p-type.
Next, a p-type doped AlqInrGa1-q-rN, where 0≦q, r, q+r≦1, layer is deposited above the active layer. The p-type layer may be doped with Mg, to a level between about 1017 cm−3 and 1021 cm−3, and may have a thickness between about 5 nm and about 500 nm. The outermost 1-30 nm of the p-type layer may be doped more heavily than the rest of the layer, so as to enable an improved electrical contact.
A reflective electrical contact, with a reflectivity greater than about 70%, is then deposited on the p-type semiconductor layer or on the second n-type layer above a tunnel junction, if it is present. In another embodiment, the reflective electrical contact is placed on the n-type side of the device structure. In a preferred embodiment, the reflectivity of the reflective electrical contact is greater than 80% or greater than 90%. The reflective electrical contact may comprise at least one of silver, gold, aluminum, nickel, platinum, rhodium, palladium, chromium, or the like. The reflective electrical contact may be deposited by thermal evaporation, electron beam evaporation, sputtering, or another suitable technique. In a preferred embodiment, the reflective electrical contact serves as the p-type electrode for the textured-surface LED. In another embodiment, the reflective electrical contact serves as an n-type electrode for the textured-surface LED. Further details of the present invention are found throughout the present specification and more particularly below. Of course, there can be other variations, modifications, and alternatives.
As is shown in the
In device operation, the defects are disadvantageous, by dramatically degrading the electro-static discharge characteristics of the device. Specifically, the presence of defects within the p type, n type and active layers of the device provide regions that reduce the breakdown voltage of the device. This occurs as a result of electrostatic events that produce undesirable charge within the device. The defects serve as conduction pathways through which the charge is transmitted. The large amount of current that is generated within these defects, greatly increases device temperature and causes overall damage to the device, as the charge is not uniformly dissipated throughout the entire device. The subsequent damage and currents cause by individual or repeated electro-static discharge events decrease the break down voltage leading to reduced performance characteristics and subsequent failure of the LED device. Thus, in order to improve applications utilizing such LED devices it is often necessary to provide LEDs with improved electro-static discharge characteristics.
The optical device of the present invention is fabricated within the epitaxial layer according to a specific embodiment. The device has a p type region layered on top of a n type region in order to create a diode structure. The active region is formed at the junction of the p and n type regions and includes another dopant in order to achieve improved light emission characteristics. The present device substantially eliminates the existence of defects extending from the substrate material into the actual device structure, including the active region in the epitaxial layer. As the defects typically are orientated along the c plane of the GaN substrate material, in using m plane GaN substrate material such defects are generally parallel to the surface of the GaN substrate material, and as a result do not extend into the epitaxial layer. Such defects still exist however at a surface density of at least 1×106 cm-2 within the bulk substrate material.
By reducing the dislocation density within the epitaxial layer, and more specifically through the active layer of the optical device, the electro-static discharge characteristics of the optical device are improved. This leads to improve reliability of devices using such LED devices, including systems that use multiple LED arrays. Specifically, as shown in
In testing the electro-static discharge characteristics of an LED device, a model circuit, shown in
After the LED is exposed to single or numerous electro-static discharge events, the current voltage I-V relationship of the LED is characterized, to determine if breakdown of the device has occurred. The highest voltage caused by electrostatic discharge at which the device can still operate is known as the ESD breakdown voltage. As shown previously the highest break down voltages are achieved when the surface defect density is minimized. As the surface defect density increases, the break down voltage decreases. LEDs that have higher ESD breakdown voltages are capable of withstanding either electro-static discharge events that generate greater amounts of charge, or multiple electro-static discharge events. The sensitivity of a device to electro-static discharge simulated by the human body model are categorized into specific classes as shown in
While the above is a full description of the specific embodiments, various modifications, alternative constructions and equivalents may be used. As an example, the packaged device can include any combination of elements described above, as well as outside of the present specification. Therefore, the above description and illustrations should not be taken as limiting the scope of the present invention which is defined by the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
4065688 | Thornton | Dec 1977 | A |
4870045 | Gasper et al. | Sep 1989 | A |
5331654 | Jewell et al. | Jul 1994 | A |
5607899 | Yoshida et al. | Mar 1997 | A |
5632812 | Hirabayashi | May 1997 | A |
5764674 | Hibbs-Brenner et al. | Jun 1998 | A |
5813753 | Vriens et al. | Sep 1998 | A |
6204602 | Yang et al. | Mar 2001 | B1 |
6335771 | Hiraishi | Jan 2002 | B1 |
6498355 | Harrah et al. | Dec 2002 | B1 |
6501154 | Morita et al. | Dec 2002 | B2 |
6509651 | Matsubara et al. | Jan 2003 | B1 |
D471881 | Hegde | Mar 2003 | S |
6533874 | Vaudo et al. | Mar 2003 | B1 |
6547249 | Collins, III et al. | Apr 2003 | B2 |
6639925 | Niwa et al. | Oct 2003 | B2 |
6680959 | Tanabe et al. | Jan 2004 | B2 |
6734461 | Shiomi et al. | May 2004 | B1 |
6787999 | Stimac et al. | Sep 2004 | B2 |
6809781 | Setlur et al. | Oct 2004 | B2 |
6858882 | Tsuda et al. | Feb 2005 | B2 |
6936488 | D'Evelyn et al. | Aug 2005 | B2 |
6956246 | Epler et al. | Oct 2005 | B1 |
6964877 | Chen et al. | Nov 2005 | B2 |
7009199 | Hall | Mar 2006 | B2 |
7012279 | Wierer, Jr. et al. | Mar 2006 | B2 |
7128849 | Setlur et al. | Oct 2006 | B2 |
D545457 | Chen | Jun 2007 | S |
7285801 | Eliashevich et al. | Oct 2007 | B2 |
7303630 | Motoki et al. | Dec 2007 | B2 |
7341880 | Erchak et al. | Mar 2008 | B2 |
7344279 | Mueller et al. | Mar 2008 | B2 |
7358542 | Radkov et al. | Apr 2008 | B2 |
7358543 | Chua et al. | Apr 2008 | B2 |
7390359 | Miyanaga et al. | Jun 2008 | B2 |
7419281 | Porchia et al. | Sep 2008 | B2 |
D581583 | Peng | Nov 2008 | S |
7470938 | Lee et al. | Dec 2008 | B2 |
7483466 | Uchida et al. | Jan 2009 | B2 |
7489441 | Scheible et al. | Feb 2009 | B2 |
D592613 | Plonski et al. | May 2009 | S |
7622742 | Kim et al. | Nov 2009 | B2 |
7637635 | Xiao et al. | Dec 2009 | B2 |
7658528 | Hoelen et al. | Feb 2010 | B2 |
7663229 | Lu et al. | Feb 2010 | B2 |
7674015 | Chien | Mar 2010 | B2 |
D618634 | Lin et al. | Jun 2010 | S |
7733571 | Li | Jun 2010 | B1 |
7744259 | Walczak et al. | Jun 2010 | B2 |
D619551 | Lin et al. | Jul 2010 | S |
7816238 | Osada et al. | Oct 2010 | B2 |
7824075 | Maxik | Nov 2010 | B2 |
7858408 | Mueller et al. | Dec 2010 | B2 |
7862761 | Okushima et al. | Jan 2011 | B2 |
7871839 | Lee et al. | Jan 2011 | B2 |
7884538 | Mitsuishi et al. | Feb 2011 | B2 |
7923741 | Zhai et al. | Apr 2011 | B1 |
7972040 | Li et al. | Jul 2011 | B2 |
7993031 | Grajcar | Aug 2011 | B2 |
8044412 | Murphy et al. | Oct 2011 | B2 |
D652564 | Maxik | Jan 2012 | S |
8142566 | Kiyomi et al. | Mar 2012 | B2 |
8188504 | Lee | May 2012 | B2 |
8198643 | Lee et al. | Jun 2012 | B2 |
8207548 | Nagai | Jun 2012 | B2 |
8207554 | Shum | Jun 2012 | B2 |
D662899 | Shum et al. | Jul 2012 | S |
D662900 | Shum et al. | Jul 2012 | S |
8227962 | Su | Jul 2012 | B1 |
8247886 | Sharma et al. | Aug 2012 | B1 |
8247887 | Raring et al. | Aug 2012 | B1 |
8252662 | Poblenz et al. | Aug 2012 | B1 |
8272762 | Maxik et al. | Sep 2012 | B2 |
8293551 | Sharma et al. | Oct 2012 | B2 |
8310143 | Van De Ven et al. | Nov 2012 | B2 |
8314429 | Raring et al. | Nov 2012 | B1 |
8324835 | Shum et al. | Dec 2012 | B2 |
D674960 | Chen et al. | Jan 2013 | S |
8350273 | Vielemeyer | Jan 2013 | B2 |
8405947 | Green et al. | Mar 2013 | B1 |
8414151 | Allen et al. | Apr 2013 | B2 |
8455894 | D'Evelyn et al. | Jun 2013 | B1 |
8502465 | Katona et al. | Aug 2013 | B2 |
8524578 | Raring et al. | Sep 2013 | B1 |
8525396 | Shum et al. | Sep 2013 | B2 |
8575728 | Raring et al. | Nov 2013 | B1 |
20010009134 | Kim et al. | Jul 2001 | A1 |
20010043042 | Murazaki et al. | Nov 2001 | A1 |
20010048114 | Morita et al. | Dec 2001 | A1 |
20010055208 | Kimura | Dec 2001 | A1 |
20020070416 | Morse et al. | Jun 2002 | A1 |
20020096994 | Iwafuchi et al. | Jul 2002 | A1 |
20020105986 | Yamasaki | Aug 2002 | A1 |
20020155691 | Lee et al. | Oct 2002 | A1 |
20020182768 | Morse et al. | Dec 2002 | A1 |
20030000453 | Unno et al. | Jan 2003 | A1 |
20030001238 | Ban | Jan 2003 | A1 |
20030020087 | Goto et al. | Jan 2003 | A1 |
20030039122 | Cao | Feb 2003 | A1 |
20030047076 | Liu | Mar 2003 | A1 |
20030058650 | Shih | Mar 2003 | A1 |
20030164507 | Edmond et al. | Sep 2003 | A1 |
20040070004 | Eliashevich et al. | Apr 2004 | A1 |
20040080256 | Hampden-Smith et al. | Apr 2004 | A1 |
20040104391 | Maeda et al. | Jun 2004 | A1 |
20040116033 | Ouderkirk et al. | Jun 2004 | A1 |
20040124435 | D'Evelyn et al. | Jul 2004 | A1 |
20040161222 | Niida et al. | Aug 2004 | A1 |
20040207998 | Suehiro et al. | Oct 2004 | A1 |
20040251471 | Dwilinski et al. | Dec 2004 | A1 |
20040264195 | Chang et al. | Dec 2004 | A1 |
20050087753 | D'Evelyn et al. | Apr 2005 | A1 |
20050121679 | Nagahama et al. | Jun 2005 | A1 |
20050167680 | Shei et al. | Aug 2005 | A1 |
20050174780 | Park | Aug 2005 | A1 |
20050199899 | Lin et al. | Sep 2005 | A1 |
20050214992 | Chakraborty et al. | Sep 2005 | A1 |
20050224830 | Blonder et al. | Oct 2005 | A1 |
20050263791 | Yanagihara et al. | Dec 2005 | A1 |
20060038542 | Park et al. | Feb 2006 | A1 |
20060060131 | Atanackovic | Mar 2006 | A1 |
20060060872 | Edmond et al. | Mar 2006 | A1 |
20060079082 | Bruhns et al. | Apr 2006 | A1 |
20060118799 | D'Evelyn et al. | Jun 2006 | A1 |
20060163589 | Fan et al. | Jul 2006 | A1 |
20060166390 | Letertre et al. | Jul 2006 | A1 |
20060169993 | Fan et al. | Aug 2006 | A1 |
20060189098 | Edmond | Aug 2006 | A1 |
20060213429 | Motoki et al. | Sep 2006 | A1 |
20060214287 | Ogihara et al. | Sep 2006 | A1 |
20060255343 | Ogihara et al. | Nov 2006 | A1 |
20060262545 | Piepgras et al. | Nov 2006 | A1 |
20060273339 | Steigerwald et al. | Dec 2006 | A1 |
20070007898 | Bruning | Jan 2007 | A1 |
20070045200 | Moon et al. | Mar 2007 | A1 |
20070054476 | Nakahata et al. | Mar 2007 | A1 |
20070093073 | Farrell, Jr. et al. | Apr 2007 | A1 |
20070096239 | Cao et al. | May 2007 | A1 |
20070105351 | Motoki et al. | May 2007 | A1 |
20070114569 | Wu et al. | May 2007 | A1 |
20070121690 | Fujii et al. | May 2007 | A1 |
20070131967 | Kawaguchi et al. | Jun 2007 | A1 |
20070202624 | Yoon et al. | Aug 2007 | A1 |
20070231978 | Kanamoto et al. | Oct 2007 | A1 |
20070264733 | Choi et al. | Nov 2007 | A1 |
20070280320 | Feezell et al. | Dec 2007 | A1 |
20070284564 | Biwa et al. | Dec 2007 | A1 |
20070290224 | Ogawa | Dec 2007 | A1 |
20080023691 | Jang et al. | Jan 2008 | A1 |
20080030976 | Murazaki et al. | Feb 2008 | A1 |
20080049399 | Lu et al. | Feb 2008 | A1 |
20080054290 | Shieh et al. | Mar 2008 | A1 |
20080073660 | Ohno et al. | Mar 2008 | A1 |
20080080137 | Otsuki et al. | Apr 2008 | A1 |
20080083929 | Fan et al. | Apr 2008 | A1 |
20080087919 | Tysoe et al. | Apr 2008 | A1 |
20080099777 | Erchak et al. | May 2008 | A1 |
20080106212 | Yen et al. | May 2008 | A1 |
20080121906 | Yakushiji | May 2008 | A1 |
20080128752 | Wu | Jun 2008 | A1 |
20080142781 | Lee | Jun 2008 | A1 |
20080158887 | Zhu et al. | Jul 2008 | A1 |
20080164489 | Schmidt et al. | Jul 2008 | A1 |
20080164578 | Tanikella et al. | Jul 2008 | A1 |
20080173884 | Chitnis et al. | Jul 2008 | A1 |
20080179607 | DenBaars et al. | Jul 2008 | A1 |
20080179610 | Okamoto et al. | Jul 2008 | A1 |
20080194054 | Lin et al. | Aug 2008 | A1 |
20080198881 | Farrell et al. | Aug 2008 | A1 |
20080211416 | Negley et al. | Sep 2008 | A1 |
20080217745 | Miyanaga et al. | Sep 2008 | A1 |
20080230765 | Yoon et al. | Sep 2008 | A1 |
20080237569 | Nago et al. | Oct 2008 | A1 |
20080266866 | Tsai | Oct 2008 | A1 |
20080272463 | Butcher et al. | Nov 2008 | A1 |
20080282978 | Butcher et al. | Nov 2008 | A1 |
20080283851 | Akita | Nov 2008 | A1 |
20080284346 | Lee | Nov 2008 | A1 |
20080285609 | Ohta et al. | Nov 2008 | A1 |
20080298409 | Yamashita et al. | Dec 2008 | A1 |
20080303033 | Brandes | Dec 2008 | A1 |
20090065798 | Masui et al. | Mar 2009 | A1 |
20090072252 | Son et al. | Mar 2009 | A1 |
20090078955 | Fan et al. | Mar 2009 | A1 |
20090081857 | Hanser et al. | Mar 2009 | A1 |
20090086475 | Caruso et al. | Apr 2009 | A1 |
20090095973 | Tanaka et al. | Apr 2009 | A1 |
20090134421 | Negley | May 2009 | A1 |
20090140279 | Zimmerman et al. | Jun 2009 | A1 |
20090146170 | Zhong et al. | Jun 2009 | A1 |
20090154166 | Zhang et al. | Jun 2009 | A1 |
20090161356 | Negley et al. | Jun 2009 | A1 |
20090194796 | Hashimoto et al. | Aug 2009 | A1 |
20090195186 | Guest et al. | Aug 2009 | A1 |
20090206354 | Kitano et al. | Aug 2009 | A1 |
20090227056 | Kyono et al. | Sep 2009 | A1 |
20090244899 | Chyn | Oct 2009 | A1 |
20090250686 | Sato et al. | Oct 2009 | A1 |
20090267098 | Choi | Oct 2009 | A1 |
20090273005 | Lin | Nov 2009 | A1 |
20090309110 | Raring et al. | Dec 2009 | A1 |
20090315480 | Yan et al. | Dec 2009 | A1 |
20090321778 | Chen et al. | Dec 2009 | A1 |
20100001300 | Raring et al. | Jan 2010 | A1 |
20100006873 | Raring et al. | Jan 2010 | A1 |
20100025656 | Raring et al. | Feb 2010 | A1 |
20100032691 | Kim | Feb 2010 | A1 |
20100055819 | Ohba et al. | Mar 2010 | A1 |
20100060130 | Li | Mar 2010 | A1 |
20100091487 | Shin | Apr 2010 | A1 |
20100108985 | Chung et al. | May 2010 | A1 |
20100109030 | Krames et al. | May 2010 | A1 |
20100117101 | Kim et al. | May 2010 | A1 |
20100117106 | Trottier | May 2010 | A1 |
20100117118 | Dabiran et al. | May 2010 | A1 |
20100148145 | Ishibashi et al. | Jun 2010 | A1 |
20100155746 | Ibbetson et al. | Jun 2010 | A1 |
20100195687 | Okamoto et al. | Aug 2010 | A1 |
20100207502 | Cao et al. | Aug 2010 | A1 |
20100207534 | Dowling et al. | Aug 2010 | A1 |
20100219505 | D'Evelyn et al. | Sep 2010 | A1 |
20100220262 | DeMille et al. | Sep 2010 | A1 |
20100240158 | Ter-Hovhannissian | Sep 2010 | A1 |
20100264799 | Liu et al. | Oct 2010 | A1 |
20100277068 | Broitzman | Nov 2010 | A1 |
20100290208 | Pickard | Nov 2010 | A1 |
20100295088 | D'Evelyn et al. | Nov 2010 | A1 |
20100309943 | Chakraborty et al. | Dec 2010 | A1 |
20100320499 | Catalano et al. | Dec 2010 | A1 |
20110017298 | Lee | Jan 2011 | A1 |
20110032708 | Johnston et al. | Feb 2011 | A1 |
20110056429 | Raring et al. | Mar 2011 | A1 |
20110075694 | Yoshizumi et al. | Mar 2011 | A1 |
20110095686 | Falicoff et al. | Apr 2011 | A1 |
20110101400 | Chu et al. | May 2011 | A1 |
20110101414 | Thompson et al. | May 2011 | A1 |
20110108081 | Werthen et al. | May 2011 | A1 |
20110124139 | Chang | May 2011 | A1 |
20110140586 | Wang | Jun 2011 | A1 |
20110169406 | Weekamp et al. | Jul 2011 | A1 |
20110175200 | Yoshida | Jul 2011 | A1 |
20110175510 | Rains, Jr. et al. | Jul 2011 | A1 |
20110180781 | Raring et al. | Jul 2011 | A1 |
20110182056 | Trottier et al. | Jul 2011 | A1 |
20110182065 | Negley et al. | Jul 2011 | A1 |
20110186860 | Enya et al. | Aug 2011 | A1 |
20110186874 | Shum | Aug 2011 | A1 |
20110198979 | Shum et al. | Aug 2011 | A1 |
20110204763 | Shum et al. | Aug 2011 | A1 |
20110204779 | Shum et al. | Aug 2011 | A1 |
20110204780 | Shum et al. | Aug 2011 | A1 |
20110216795 | Hsu et al. | Sep 2011 | A1 |
20110242823 | Tracy et al. | Oct 2011 | A1 |
20110266552 | Tu et al. | Nov 2011 | A1 |
20110309734 | Lin et al. | Dec 2011 | A1 |
20120007102 | Feezell et al. | Jan 2012 | A1 |
20120104412 | Zhong et al. | May 2012 | A1 |
20120135553 | Felker et al. | May 2012 | A1 |
20120161626 | van De Ven et al. | Jun 2012 | A1 |
20120187412 | D'Evelyn et al. | Jul 2012 | A1 |
20120187830 | Shum et al. | Jul 2012 | A1 |
20120199841 | Batres et al. | Aug 2012 | A1 |
20120288974 | Sharma et al. | Nov 2012 | A1 |
20130022758 | Trottier | Jan 2013 | A1 |
20130026483 | Sharma et al. | Jan 2013 | A1 |
20130058099 | Shum et al. | Mar 2013 | A1 |
20130112987 | Fu et al. | May 2013 | A1 |
20130126902 | Isozaki et al. | May 2013 | A1 |
20130234108 | David et al. | Sep 2013 | A1 |
Number | Date | Country |
---|---|---|
2381490 | Oct 2011 | EP |
06-334215 | Dec 1994 | JP |
2007-110090 | Apr 2007 | JP |
2008-084973 | Apr 2008 | JP |
2008-172040 | Jul 2008 | JP |
WO 2006062880 | Jun 2006 | WO |
WO 2009001039 | Dec 2008 | WO |
WO 2011054716 | May 2011 | WO |
Entry |
---|
Haskell et al (Defect Reduction in (1100) m-plane gallium nitride via laterla epitaxial overgrowth by hydride vapor phase epitaxy, Applied Physics Letters 86, 111917 (2005), pp. 1-3). |
USPTO Office Action for U.S. Appl. No. 13/025,833 dated Jul. 12, 2012. |
Farrell et al., ‘Continuous-Wave Operation of AIGaN-Cladding-Free Nonpolar m-Plane InGaN/GaN Laser Diodes,’ 2007, Japanese Journal of Applied Physics, vol. 46, No. 32, 2007, pp. L761-L763. |
Feezell et al., ‘AIGaN-Cladding-Free Nonpolar InGaN/GaN Laser Diodes,’ Japanese Journal of Applied Physics, vol. 46, No. 13, 2007, pp. L284-L286. |
Kojima et al., ‘Stimulated Emission At 474 nm From an InGaN Laser Diode Structure Grown on a (1122) GaN Substrate,’ Applied Physics Letters, vol. 91, 2007, pp. 251107-251107-3. |
Kubota et al., ‘Temperature Dependence of Polarized Photoluminescence From Nonpolar m-Plane InGaN Multiple Quantum Wells for Blue Laser Diodes,’ Applied Physics Letter, vol. 92, 2008, pp. 011920-1-011920-3. |
PCT Communication Including Partial Search and Examination Report for PCT/US2011/41106, dated Oct. 4, 2011, 2 pages total. |
International Search Report for PCT application PCT/US2011/41106 (Jan. 5, 2012). |
Tsuda et al., ‘Blue Laser Diodes Fabricated on m-Plane GaN Substrates,’ Applied Physics Express, vol. 1, 2008, pp. 011104-1-011104-3. |
Tyagi et al., ‘Semipolar (1011) InGaN/GaN Laser Diodes on Bulk GaN Substrates,’ Japanese Journal of Applied Physics, vol. 46, No. 19, 2007, pp. L444-L445. |
USPTO Office Action for U.S. Appl. No. 12/478,736 dated Feb. 7, 2012. |
USPTO Office Action for U.S. Appl. No. 13/025,791 dated Nov. 25, 2011. |
USPTO Office Action for U.S. Appl. No. 13/025,833 dated Dec. 14, 2011. |
USPTO Office Action for U.S. Appl. No. 13/025,860 dated Dec. 30, 2011. |
USPTO Notice of Allowance for U.S. Appl. No. 13/025,860 dated Jun. 8, 2012. |
USPTO Office Action for U.S. Appl. No. 13/025,791 dated Feb. 20, 2013. |
USPTO Office Action for U.S. Appl. No. 13/025,849 dated Mar. 15, 2013. |
USPTO Notice of Allowance for U.S. Appl. No. 29/399,523 dated Mar. 5, 2012. |
USPTO Notice of Allowance for U.S. Appl. No. 29/399,524 dated Mar. 2, 2012. |
International Preliminary Report & Written Opinion of PCT Application No. PCT/US2011/060030 dated Mar. 21, 2012, 11 pgs. total. |
CFL Ballast IC Drive LED, www.placardshop.com, Blog, May 22, 2012, 3 pgs. |
Rausch, ‘Use a CFL ballast to drive LEDs’, EDN Network, 2007, pp. 1-2. |
USPTO Notice of Allowance for U.S. Appl. No. 13/025,791 dated Jun. 17, 2013. |
USPTO Office Action for U.S. Appl. No. 13/025,833 dated Apr. 26, 2013. |
USPTO Notice of Allowance for U.S. Appl. No. 13/025,849 dated Sep. 16, 2013, 10 pages. |
USPTO Office Action for U.S. Appl. No. 13/274,489 dated Sep. 6, 2013, 13 pages. |
USPTO Office Action for U.S. Appl. No. 13/535,142 dated Aug. 1, 2013, 14 pages. |
USPTO Notice of Allowance for U.S. Appl. No. 29/423,725 dated Jul. 19, 2013, 11 pages. |
Aguilar, ‘Ohmic n-contacts to Gallium Nitride Light Emitting Diodes’, National Nanotechnologhy Infrastructure Network, 2007, p. 56-81. |
Baker et al., ‘Characterization of Planar Semipolar Gallium Nitride Films on Spinel Substrates’, Japanese Journal of Applied Physics, vol. 44, No. 29, 2005, pp. L920-L922. |
Benke et al., ‘Uncertainty in Health Risks from Artificial Lighting due to Disruption of Circadian Rythm and Melatonin Secretion: A Review’, Human and Ecological Risk Assessment: An International Journal, vol. 19, No. 4, 2013, pp. 916-929. |
Cich et al., ‘Bulk GaN based violet light-emitting diodes with high efficiency at very high current density’, Applied Physics Letters, Nov. 29, 2012, pp. 223509-1-223509-3. |
Founta et al., ‘Anisotropic Morphology of Nonpolar a-Plane GaN Quantum Dots and Quantum Wells’, Journal of Applied Physics, vol. 102, vol. 7, 2007, pp. 074304-1-074304-6. |
Hanifin et al., ‘Photoreception for Circadian, Neuroendocrine, and Neurobehavioral Regulation’, Journal of Physiological Anthropology, vol. 26, 2007, pp. 87-94. |
Iso et al., ‘High Brightness Blue InGaN/GaN Light Emitting Diode on Nonpolar m-Plane Bulk GaN Substrate’, Japanese Journal of Applied Physics, vol. 46, No. 40, 2007, pp. L960-L962. |
Kim et al., ‘High Brightness Light Emitting Diodes Using Dislocation-Free Indium Gallium Nitride/Gallium Nitride Multiquantum-Well Nanorod Arrays’, Nano Letters, vol. 4, No. 6, 2004, pp. 1059-1062. |
Lu et al., ‘Etch-Pits of GaN Films with Different Etching Methods’, Journal of the Korean Physical Society, vol. 45, Dec. 2004, p. S673-S675. |
International Search Report & Written Opinion of PCT Application No. PCT/US2013/029453, dated Jul. 25, 2013, 11 pages total. |
http://www.philipslumileds.com/products/luxeon-flash, ‘LUXEON Flash’, Philips Lumileds, Aug. 8, 2013, pp. 1-2. |
Rea et al., ‘White Lighting’, COLOR Research and Application, vol. 38, No. 2, Sep. 3, 2011, pp. 82-92. |
Rickert et al., ‘n-GaN Surface Treatments for Metal Contacts Studied Via X-ray Photoemission Spectroscopy’, Applied Physics Letters, vol. 80, No. 2, Jan. 14, 2002, p. 204-206. |
Sato et al., ‘High Power and High Efficiency Semipolar InGaN Light Emitting Diodes’, Journal of Light and Visible Environment, vol. 32, No. 2, Dec. 13, 2007, pp. 57-60. |
Sato et al., ‘Optical Properties of Yellow Light-Emitting Diodes Grown on Semipolar (1122) Bulk GaN Substrate’, Applied Physics Letters, vol. 92, No. 22, 2008, pp. 221110-1-221110-3. |
Selvanathan et al., ‘Investigation of Surface Treatment Schemes on n-type GaN and A1 0.20Ga0.80N’, Journal of Vacuum Science and Technology B, vol. 23, No. 6, May 10, 2005, p. 2538-2544. |
Semendy et al., ‘Observation and Study of Dislocation Etch Pits in Molecular Beam Epitaxy Grown Gallium Nitride with the use of Phosphoric Acid and Molten Potassium Hydroxide’, Army Research Laboratory, Jun. 2007, 18 pages. |
Communication from the Korean Patent Office re 10-2012-7009980 dated Apr. 15, 2013, (6 pages). |
Communication from the Japanese Patent Office re 2012-529969, dated Oct. 15, 2013, (6 pages). |
Weaver et al., ‘Optical Properties of Selected Elements’, Handbook of Chemistry and Physics, 94th Edition, 2013-2014, pp. 12-126-12-150. |
USPTO Office Action for U.S. Appl. No. 12/481,543 dated Jun. 27, 2011 (9 pages). |
USPTO Office Action for U.S. Appl. No. 12/491,169 dated Oct. 22, 2010 (9 pages). |
USPTO Office Action for U.S. Appl. No. 12/491,169 dated May 11, 2011 (9 pages). |
USPTO Office Action for U.S. Appl. No. 12/497,289 dated Feb. 2, 2012 (6 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 12/497,289 dated May 22, 2012 (7 pages). |
USPTO Office Action for U.S. Appl. No. 12/569,841 dated Dec. 23, 2011 (12 pages). |
USPTO Office Action for U.S. Appl. No. 12/569,841 dated Mar. 26, 2013 (17 pages). |
USPTO Office Action for U.S. Appl. No. 12/569,841 dated Aug. 13, 2013 (20 pages). |
USPTO Office Action for U.S. Appl. No. 12/569,844 dated Oct. 12, 2012 (12 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 12/569,844 dated Mar. 7, 2013 (9 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 12/720,593 dated Jul. 11, 2012 (7 pages). |
USPTO Office Action for U.S. Appl. No. 12/749,466 dated Jul. 3, 2012 (18 pages). |
USPTO Office Action for U.S. Appl. No. 12/749,476 dated Apr. 11, 2011 (14 pages). |
USPTO Office Action for U.S. Appl. No. 12/749,476 dated Nov. 8, 2011 (11 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 12/749,476 dated May 4, 2012 (8 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 12/749,476 dated Jun. 26, 2012 (8 pages). |
USPTO Office Action for U.S. Appl. No. 12/861,765 dated Jul. 2, 2012 (11 pages). |
USPTO Office Action for U.S. Appl. No. 12/861,765 dated Mar. 7, 2013 (12 pages). |
USPTO Office Action for U.S. Appl. No. 12/861,765 dated Sep. 17, 2013 (10 pages). |
USPTO Office Action for U.S. Appl. No. 12/879,784 dated Jan. 25, 2012 (6 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 12/879,784 dated Apr. 3, 2012 (7 pages). |
USPTO Office Action for U.S. Appl. No. 12/880,803 dated Feb. 22, 2012 (8 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 12/880,803 dated Jul. 18, 2012 (5 pages). |
USPTO Office Action for U.S. Appl. No. 12/936,238 dated Aug. 30, 2012 (11 pages). |
USPTO Office Action for U.S. Appl. No. 12/936,238 dated Jan. 30, 2013 (12 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 12/936,238 dated Apr. 16, 2013 (9 pages). |
USPTO Office Action for U.S. Appl. No. 12/995,946 dated Mar. 28, 2012 (17 pages). |
USPTO Office Action for U.S. Appl. No. 12/995,946 dated Jan. 29, 2013 (25 pages). |
USPTO Office Action for U.S. Appl. No. 12/995,946 dated Aug. 2, 2013 (15 pages). |
USPTO Office Action for U.S. Appl. No. 13/014,622 dated Nov. 28, 2011 (13 pages). |
USPTO Office Action for U.S. Appl. No. 13/014,622 dated Apr. 30, 2012 (13 pages). |
USPTO Office Action for U.S. Appl. No. 13/019,897 dated Mar. 30, 2012 (14 pages). |
USPTO Office Action for U.S. Appl. No. 13/019,897 dated Jan. 16, 2013 (7 pages). |
USPTO Office Action for U.S. Appl. No. 13/019,897 dated Dec. 2, 2013 (17 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 13/163,482 dated Jul. 31, 2012 (5 pages). |
USPTO Office Action for U.S. Appl. No. 13/179,346 dated Aug. 17, 2012 (17 pages). |
USPTO Office Action for U.S. Appl. No. 13/179,346 dated Dec. 13, 2012 (20 pages). |
USPTO Office Action for U.S. Appl. No. 13/281,221 dated Jun. 21, 2013 (6 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 13/281,221 dated Nov. 12, 2013 (10 pages). |
USPTO Office Action for U.S. Appl. No. 13/328,978 dated May 15, 2013 (24 pages). |
USPTO Office Action for U.S. Appl. No. 13/328,978 dated Sep. 26, 2013 (25 pages). |
USPTO Office Action for U.S. Appl. No. 13/465,976 dated Aug. 16, 2012 (16 pages). |
USPTO Office Action for U.S. Appl. No. 13/465,976 dated Dec. 20, 2012 (16 pages). |
USPTO Office Action for U.S. Appl. No. 13/548,635 dated Jun. 14, 2013 (5 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 13/548,635 dated Sep. 16, 2013 (6 pages). |
USPTO Office Action for U.S. Appl. No. 13/548,312 dated Mar. 12, 2013 (5 pages). |
USPTO Notice of Allowance for U.S. Appl. No. 13/548,770 dated Jun. 25, 2013 (6 pages). |
USPTO Office Action for U.S. Appl. No. 13/629,366 dated Oct. 31, 2013 (7 pages). |
USPTO Office Action for U.S. Appl. No. 13/723,968 dated Nov. 29, 2013 (23 pages). |
Number | Date | Country | |
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61181515 | May 2009 | US |