International Business Machines Corporation, a New York corporation; Macronix International Corporation, Ltd., a Taiwan corporation; and Infineon Technologies AG, a German corporation, are parties to a Joint Research Agreement.
1. Field of the Invention
The present invention relates to high density memory devices based on phase change based memory materials, including chalcogenide based materials and other materials, and to methods for manufacturing such devices.
2. Description of Related Art
Phase change based memory materials are widely used in read-write optical disks. These materials have at least two solid phases, including for example a generally amorphous solid phase and a generally crystalline solid phase. Laser pulses are used in read-write optical disks to switch between phases and to read the optical properties of the material after the phase change.
Phase change based memory materials, like chalcogenide based materials and similar materials, also can be caused to change phase by application of electrical current at levels suitable for implementation in integrated circuits. The generally amorphous state is characterized by higher resistivity than the generally crystalline state, which can be readily sensed to indicate data. These properties have generated interest in using programmable resistive material to form nonvolatile memory circuits, which can be read and written with random access.
The change from the amorphous to the crystalline state is generally a lower current operation. The change from crystalline to amorphous, referred to as reset herein, is generally a higher current operation, which includes a short high current density pulse to melt or breakdown the crystalline structure, after which the phase change material cools quickly, quenching the phase change process, allowing at least a portion of the phase change structure to stabilize in the amorphous state. It is desirable to minimize the magnitude of the reset current used to cause transition of phase change material from crystalline state to amorphous state. The magnitude of the reset current needed for reset can be reduced by reducing the size of the phase change material element in the cell and of the contact area between electrodes and the phase change material, so that higher current densities are achieved with small absolute current values through the phase change material element.
One direction of development has been toward forming small pores in an integrated circuit structure, and using small quantities of programmable resistive material to fill the small pores. Patents illustrating development toward small pores include: Ovshinsky, “Multibit Single Cell Memory Element Having Tapered Contact,” U.S. Pat. No. 5,687,112, issued Nov. 11, 1997; Zahorik et al., “Method of Making Chalogenide [sic] Memory Device,” U.S. Pat. No. 5,789,277, issued Aug. 4, 1998; Doan et al., “Controllable Ovonic Phase-Change Semiconductor Memory Device and Methods of Fabricating the Same,” U.S. Pat. No. 6,150,253, issued Nov. 21, 2000, and Reinberg, “Chalcogenide Memory Cell with a Plurality of Chalcogenide Electrodes,” U.S. Pat. No. 5,920,788, issued Jul. 6, 1999.
A specific issue arising from conventional phase change memory and structures is the heat sink effect of conventional designs. Generally, the prior art teaches the use of metallic electrodes on both sides of the phase change memory element, with electrodes of approximately the same size as the phase change member. Such electrodes act as heat sinks, the high heat conductivity of the metal rapidly drawing heat away from the phase change material. Because the phase change occurs as a result of heating, the heat sink effect results in a requirement for higher current, in order to effect the desired phase change.
Moreover, problems have arisen in manufacturing such devices with very small dimensions, and with variations in process that meets tight specifications needed for large-scale memory devices. It is desirable therefore to provide a memory cell structure having small dimensions and low reset currents, as well as a structure that addresses the heat conductivity problem, and a method for manufacturing such structure that meets tight process variation specifications needed for large-scale memory devices. It is further desirable to provide a manufacturing process and a structure, which are compatible with manufacturing of peripheral circuits on the same integrated circuit.
An embodiment of the present invention features a memory device including two electrodes, vertically separated and having mutually opposed contact surfaces, between which lies a phase change cell. The phase change cell includes an upper phase change member, having a contact surface in electrical contact with the first electrode; a lower phase change member, having a contact surface in electrical contact with the second electrode; and a kernel member disposed between and in electrical contact with the upper and lower phase change members. The phase change cell is formed of material having at least two solid phases, and the lateral extent of the upper and lower phase change members is substantially greater than that of the kernel member. An intermediate insulating layer is disposed between the upper and lower phase change members adjacent to the kernel member.
In another aspect of the invention, a method for constructing a phase change memory element comprises the steps of providing a substrate having an electrode element extending therethrough; depositing a first layer of phase change material having a desired thickness onto the substrate; depositing a kernel layer of phase change material, having a desired thickness and a width substantially less than the width of the first layer, onto the first phase change layer; and depositing a second phase change layer, having a desired thickness and a width substantially the same as the first layer, onto the kernel layer.
Another aspect of the invention is a computer memory array, including data communication lines for communicating word and bit enabling signals to the array and a plurality of memory cells. Each memory cell includes at least one access transistor and a phase change element, and each phase change element includes an upper phase change member; a lower phase change member; and a kernel member disposed between and in electrical contact with the upper and lower phase change members. Within the phase change member, the phase change cell is formed of material having at least two solid phases; and the lateral extent of the upper and lower phase change members is substantially greater than that of the kernel member.
Particular aspects of the present invention are described in the claims, specification and drawings, which illustrate the present invention but do not limit it. The invention is defined solely by the claims appended hereto.
The following detailed description is made with reference to the figures. Preferred embodiments are described to illustrate the present invention, not to limit its scope, which is defined by the claims. Those of ordinary skill in the art will recognize a variety of equivalent variations on the description that follows.
The structural and functional aspects of the memory cell will be discussed first, after which there will follow a detailed discussion of the process for forming the same. The cell is preferably formed on a dielectric layer or substrate 12, preferably consisting of silicon oxide or a well-known alternative thereto, such as a polyimide, silicon nitride or other dielectric fill material. In embodiments, the dielectric layer comprises a relatively good insulator for heat as well as for electricity, providing thermal and electrical isolation. An electrical contact, or plug, 14, preferably formed from a refractory metal such as tungsten, is formed in the oxide layer. Other refractory metals include Ti, Mo, Al, Ta, Cu, Pt, Ir, La, Ni, and Ru. A barrier material 16 is formed on the oxide layer, generally serving to prevent diffusion and to beneficially affect the electric field within the cell, as discussed below. The barrier layer is preferably formed of titanium nitride (TiN) or similar material, such as one or more elements selected from the group consisting of Si, Ti, Al, Ta, N, O, and C. It should be noted that, for purposes of reference only, the direction from the bottom toward the top of the drawings herein is designated “vertical,” and the side-to-side direction is “lateral” or “horizontal.” Such designations have no effect on the actual physical orientation of a device, either during fabrication or during use.
Phase change element 17 consists primarily of a lower phase change element 18, a kernel element 26, and an upper phase change element 28. Generally, the upper and lower phase change elements have a considerably greater volume than that of the kernel element, and the element is preferably formed as a vertical stack, with the lower phase change element being positioned atop the dielectric layer 12, the kernel element atop the lower phase change element, and the upper phase change element atop the kernel element, in sandwich fashion. The lateral extent of the upper and lower phase change members is significantly greater than that of the kernel element. Those in the art will be able to choose specific values for these parameters, given the requirements of specific design situations.
A dielectric layer 22, preferably formed from silicon dioxide, separates the portions of the two phase change elements extending outwardly from the kernel. One embodiment of the invention includes a barrier metal layer 20 atop the lower phase change element, between that element and the oxide layer. Another layer of barrier metal 24 may be interposed between the dielectric layer 22 and the upper phase change element 28. In embodiments where barrier layer 24 is employed, the barrier does not extend between kernel element 26 and the upper phase change element 28. An upper layer of barrier metal forms an electrode layer 30, which also acts as a diffusion barrier.
Dimensions of the memory cell elements are as follows. Upper and lower phase change elements have thicknesses (in the vertical dimension) of from about 10 nm to about 100 nm, preferably 40 nm. Kernel element 26 has a thickness of from about 10 nm to about 100 nm, preferably 40 nm. Insulating layer 22 has the same thickness as the kernel layer. The barrier layers 16, 20 and 24 have thicknesses of from about 5 nm to about 30 nm, preferably 10 nm. The electrode layer 30 has a thickness of from about 10 nm to about 300 nm, preferably 150 nm. Kernel element 26 further has a width (in the horizontal dimension of
Embodiments of memory cell device 10 include phase change based memory materials, including chalcogenide based materials and other materials, for memory material 20. Chalcogens include any of the four elements oxygen (O), sulfur (S), selenium (Se), and tellurium (Te), forming part of group VI of the periodic table. Chalcogenides comprise compounds of a chalcogen with a more electropositive element or radical. Chalcogenide alloys comprise combinations of chalcogenides with other materials such as transition metals. A chalcogenide alloy usually contains one or more elements from Group IV of the periodic table of elements, such as germanium (Ge) and tin (Sn). Often, chalcogenide alloys include combinations including one or more of antimony (Sb), gallium (Ga), indium (In), and silver (Ag). Many phase change based memory materials have been described in technical literature, including alloys of: Ga/Sb, In/Sb, In/Se, Sb/Te, Ge/Te, Ge/Sb/Te, In/Sb/Te, Ga/Se/Te, Sn/Sb/Te, In/Sb/Ge, Ag/In/Sb/Te, Ge/Sn/Sb/Te, Ge/Sb/Se/Te and Te/Ge/Sb/S. In the family of Ge/Sb/Te alloys, a wide range of alloy compositions may be workable. The compositions can be characterized as TeaGebSb100−(a+b). One researcher has described the most useful alloys as having an average concentration of Te in the deposited materials well below 70%, typically below about 60% and ranged in general from as low as about 23% up to about 58% Te and most preferably about 48% to 58% Te. Concentrations of Ge were above about 5% and ranged from a low of about 8% to about 30% average in the material, remaining generally below 50%. Most preferably, concentrations of Ge ranged from about 8% to about 40%. The remainder of the principal constituent elements in this composition was Sb. These percentages are atomic percentages that total 100% of the atoms of the constituent elements. (Ovshinsky '112 patent, columns 10-11.) Particular alloys evaluated by another researcher include Ge2Sb2Te5, GeSb2Te4and GeSb4Te7. (Noboru Yamada, “Potential of Ge—Sb—Te Phase-Change Optical Disks for High-Data-Rate Recording”, SPIE v. 3109, pp. 28-37(1997).) More generally, a transition metal such as chromium (Cr), iron (Fe), nickel (Ni), niobium (Nb), palladium (Pd), platinum (Pt) and mixtures or alloys thereof may be combined with Ge/Sb/Te to form a phase change alloy that has programmable resistive properties. Specific examples of memory materials that may be useful are given in Ovshinsky '112 at columns 11-13, which examples are hereby incorporated by reference.
Phase change alloys are capable of being switched between a first structural state in which the material is in a generally amorphous solid phase, and a second structural state in which the material is in a generally crystalline solid phase in its local order in the active channel region of the cell. These alloys are at least bistable. The term amorphous is used to refer to a relatively less ordered structure, more disordered than a single crystal, which has the detectable characteristics such as higher electrical resistivity than the crystalline phase. The term crystalline is used to refer to a relatively more ordered structure, more ordered than in an amorphous structure, which has detectable characteristics such as lower electrical resistivity than the amorphous phase. Typically, phase change materials may be electrically switched between different detectable states of local order across the spectrum between completely amorphous and completely crystalline states. Other material characteristics affected by the change between amorphous and crystalline phases include atomic order, free electron density and activation energy. The material may be switched either into different solid phases or into mixtures of two or more solid phases, providing a gray scale between completely amorphous and completely crystalline states. The electrical properties in the material may vary accordingly.
Phase change alloys can be changed from one phase state to another by application of electrical pulses. It has been observed that a shorter, higher amplitude pulse tends to change the phase change material to a generally amorphous state. A longer, lower amplitude pulse tends to change the phase change material to a generally crystalline state. The energy in a shorter, higher amplitude pulse is high enough to allow for bonds of the crystalline structure to be broken and short enough to prevent the atoms from realigning into a crystalline state. Appropriate profiles for pulses can be determined, without undue experimentation, specifically adapted to a particular phase change alloy. In following sections of the disclosure, the phase change material is referred to as GST, and it will be understood that other types of phase change materials can be used. A material useful for implementation of a PCRAM described herein is Ge2Sb2Te5.
Other programmable resistive memory materials may be used in other embodiments of the invention, including N2 doped GST, GexSby, or other material that uses different crystal phase changes to determine resistance; PrxCayMnO3, PrSrMnO, ZrOx, or other material that uses an electrical pulse to change the resistance state; TCNQ, PCBM, TCNQ-PCBM, Cu-TCNQ, Ag-TCNQ, C60-TCNQ, TCNQ doped with other metal, or any other polymer material that has bistable or multi-stable resistance state controlled by an electrical pulse.
As shown, the electric field and current density in the two phase change members are relatively low compared to the values seen in the kernel. The relatively small lateral extent of the kernel member produces current and field densities much higher than those in the phase change members, in turn leading to a significantly higher voltage drop in the kernel area. As a result, the kernel will experience much higher value of heating than will the phase change members, and in fact the phase change will be restricted to the area of the kernel. Both phase change members remain in a SET (crystalline) condition, as they never experience a current flow great enough to generate a phase change to RESET.
In addition, the low heat conductivity of the phase change members reduces the heat transfer from the kernel area, effectively increasing the amount of heat generated within the phase change material per unit value of current. The thermal isolation of the kernel area allows for memory cell design having lower currents than those permitted by the prior art, which in turn allows for reducing the size of the memory cell itself.
In addition, the GST material has significantly lower heat conductivity than does a metallic electrode, so that this design innovation has the effect of retaining heat in the kernel area rather than conducting it, away from the electrode. That leads to the ability to obtain desired phase change results with lower current, which in turn leads to reduced cell size and greater device density.
It can be readily seen from
An adaptation of the phase change memory element 10, modified to provide two phase change memory elements in a single unit, can be seen more clearly in the sectional view of
A dielectric fill layer (not illustrated) overlies the element layer 131. The dielectric fill layer comprises silicon dioxide, a polyimide, silicon nitride or other dielectric fill materials. In embodiments, the fill layer comprises a relatively good insulator for heat as well as for electricity, providing thermal and electrical isolation for the phase change elements. Conventional circuitry (not shown) is added above the element layer 131 to receive output from the phase change elements 10a and 10b.
In operation, access to the memory cell corresponding with phase change element 10a is accomplished by applying a control signal to the word line 123, which couples the common source line 128 via terminal 125 and plug 14a, to the phase change element 10a. Likewise, access to the memory cell corresponding with phase change element 10b is accomplished by applying a control signal to the word line 124.
It will be understood that a wide variety of materials can be utilized in implementation of the structure illustrated in
A controller implemented in this example using bias arrangement state machine 169 controls the application of bias arrangement supply voltages 168, such as read, program, erase, erase verify and program verify voltages. The controller can be implemented using special-purpose logic circuitry as known in the art. In alternative embodiments, the controller comprises a general-purpose processor, which may be implemented on the same integrated circuit, which executes a computer program to control the operations of the device. In yet other embodiments, a combination of special-purpose logic circuitry and a general-purpose processor may be utilized for implementation of the controller.
The process for fabricating the cell design of the present invention will be discussed in connection with
Deposition of the first layer of GST material is shown in
Any of the conventional barrier metals can be employed here, as known to those in the art. It is preferred to utilize either TiN or TaN in this application. An additional benefit of employing a metallic barrier layer is that it helps make the electric field more uniform, leading to predictable field and current profiles in the GST material.
Deposition of further GST material in
The final cell configuration 10, best seen in
It will be appreciated that fabrication of the two-element structure shown in
While the present invention is disclosed by reference to the preferred embodiments and examples detailed above, it is understood that these examples are intended in an illustrative rather than in a limiting sense. It is contemplated that modifications and combinations will readily occur to those skilled in the art, which modifications and combinations will be within the spirit of the invention and the scope of the following claims.
This application claims the benefit of U.S. Provisional Patent Application No. 60/736,720, entitled “I-Shaped Phase Change Memory Cell” by Shih Hung Chen and Hsiang-Lan Lung filed on Nov. 15, 2005. That application is incorporated by reference for all purposes.
Number | Name | Date | Kind |
---|---|---|---|
3271591 | Ovshinsky | Sep 1966 | A |
3530441 | Ovshinsky | Sep 1970 | A |
4599705 | Holmberg et al. | Jul 1986 | A |
4719594 | Young et al. | Jan 1988 | A |
4876220 | Mohsen et al. | Oct 1989 | A |
4959812 | Momodomi et al. | Sep 1990 | A |
5166096 | Cote et al. | Nov 1992 | A |
5166758 | Ovshinsky et al. | Nov 1992 | A |
5177567 | Klersy et al. | Jan 1993 | A |
5515488 | Stephens, Jr. | May 1996 | A |
5534712 | Ovshinsky et al. | Jul 1996 | A |
5687112 | Ovshinsky | Nov 1997 | A |
5789277 | Zahorik et al. | Aug 1998 | A |
5789758 | Reinberg | Aug 1998 | A |
5814527 | Wolstenholme et al. | Sep 1998 | A |
5831276 | Gonzalez et al. | Nov 1998 | A |
5837564 | Sandhu et al. | Nov 1998 | A |
5869843 | Harshfield | Feb 1999 | A |
5879955 | Gonzalez et al. | Mar 1999 | A |
5920788 | Reinberg | Jul 1999 | A |
5933365 | Klersy et al. | Aug 1999 | A |
5952671 | Reinberg et al. | Sep 1999 | A |
5958358 | Tenne et al. | Sep 1999 | A |
5970336 | Wolstenholme et al. | Oct 1999 | A |
5985698 | Gonzalez et al. | Nov 1999 | A |
5998244 | Wolstenholme et al. | Dec 1999 | A |
6011725 | Eitan | Jan 2000 | A |
6025220 | Sandhu | Feb 2000 | A |
6031287 | Harshfield | Feb 2000 | A |
6034882 | Johnson et al. | Mar 2000 | A |
6077674 | Schleifer et al. | Jun 2000 | A |
6077729 | Harshfield | Jun 2000 | A |
6087269 | Williams | Jul 2000 | A |
6087674 | Ovshinsky et al. | Jul 2000 | A |
6104038 | Gonzalez et al. | Aug 2000 | A |
6111264 | Wolstenholme et al. | Aug 2000 | A |
6114713 | Zahorik | Sep 2000 | A |
6117720 | Harshfield | Sep 2000 | A |
6147395 | Gilgen | Nov 2000 | A |
6150253 | Doan et al. | Nov 2000 | A |
6153890 | Wolstenholme et al. | Nov 2000 | A |
6177317 | Huang et al. | Jan 2001 | B1 |
6185122 | Johnson et al. | Feb 2001 | B1 |
6189582 | Reinberg et al. | Feb 2001 | B1 |
6236059 | Wolstenholme et al. | May 2001 | B1 |
RE37259 | Ovshinsky | Jul 2001 | E |
6271090 | Huang et al. | Aug 2001 | B1 |
6280684 | Yamada et al. | Aug 2001 | B1 |
6287887 | Gilgen | Sep 2001 | B1 |
6314014 | Lowrey et al. | Nov 2001 | B1 |
6320786 | Chang et al. | Nov 2001 | B1 |
6339544 | Chiang et al. | Jan 2002 | B1 |
6351406 | Johnson et al. | Feb 2002 | B1 |
6420215 | Knall et al. | Jul 2002 | B1 |
6420216 | Clevenger et al. | Jul 2002 | B1 |
6420725 | Harshfield | Jul 2002 | B1 |
6423621 | Doan et al. | Jul 2002 | B2 |
6429064 | Wicker | Aug 2002 | B1 |
6462353 | Gilgen | Oct 2002 | B1 |
6483736 | Johnson et al. | Nov 2002 | B2 |
6487114 | Jong et al. | Nov 2002 | B2 |
6501111 | Lowrey | Dec 2002 | B1 |
6507061 | Hudgens et al. | Jan 2003 | B1 |
6511867 | Lowrey et al. | Jan 2003 | B2 |
6512241 | Lai | Jan 2003 | B1 |
6514788 | Quinn | Feb 2003 | B2 |
6534781 | Dennison | Mar 2003 | B2 |
6545903 | Wu | Apr 2003 | B1 |
6555860 | Lowrey et al. | Apr 2003 | B2 |
6563156 | Harshfield | May 2003 | B2 |
6566700 | Xu | May 2003 | B2 |
6567293 | Lowrey et al. | May 2003 | B1 |
6579760 | Lung | Jun 2003 | B1 |
6586761 | Lowrey | Jul 2003 | B2 |
6589714 | Maimon et al. | Jul 2003 | B2 |
6593176 | Dennison | Jul 2003 | B2 |
6597009 | Wicker | Jul 2003 | B2 |
6605527 | Dennison et al. | Aug 2003 | B2 |
6605821 | Lee et al. | Aug 2003 | B1 |
6607974 | Harshfield | Aug 2003 | B2 |
6613604 | Maimon et al. | Sep 2003 | B2 |
6617192 | Lowrey et al. | Sep 2003 | B1 |
6621095 | Chiang et al. | Sep 2003 | B2 |
6627530 | Li et al. | Sep 2003 | B2 |
6639849 | Takahashi et al. | Oct 2003 | B2 |
6673700 | Dennison et al. | Jan 2004 | B2 |
6674115 | Hudgens et al. | Jan 2004 | B2 |
6744088 | Dennison | Jun 2004 | B1 |
6791102 | Johnson et al. | Sep 2004 | B2 |
6797979 | Chiang et al. | Sep 2004 | B2 |
6800504 | Li et al. | Oct 2004 | B2 |
6800563 | Xu | Oct 2004 | B2 |
6815704 | Chen | Nov 2004 | B1 |
6830952 | Lung et al. | Dec 2004 | B2 |
6850432 | Lu et al. | Feb 2005 | B2 |
6859389 | Idehara et al. | Feb 2005 | B2 |
6861267 | Xu et al. | Mar 2005 | B2 |
6864500 | Gilton | Mar 2005 | B2 |
6864503 | Lung | Mar 2005 | B2 |
6867638 | Saiki et al. | Mar 2005 | B2 |
6888750 | Walker et al. | May 2005 | B2 |
6894305 | Yi et al. | May 2005 | B2 |
6903362 | Wyeth et al. | Jun 2005 | B2 |
6909107 | Rodgers et al. | Jun 2005 | B2 |
6927410 | Chen | Aug 2005 | B2 |
6933516 | Xu | Aug 2005 | B2 |
6936840 | Sun et al. | Aug 2005 | B2 |
6937507 | Chen | Aug 2005 | B2 |
6992932 | Cohen | Jan 2006 | B2 |
7023009 | Kostylev et al. | Apr 2006 | B2 |
7033856 | Lung et al. | Apr 2006 | B2 |
7042001 | Kim et al. | May 2006 | B2 |
7067865 | Lung et al. | Jun 2006 | B2 |
7078273 | Matsuoka et al. | Jul 2006 | B2 |
7126149 | Iwasaki et al. | Oct 2006 | B2 |
7132675 | Gilton | Nov 2006 | B2 |
7166533 | Happ | Jan 2007 | B2 |
7214958 | Happ | May 2007 | B2 |
7220983 | Lung | May 2007 | B2 |
20030095426 | Hush et al. | May 2003 | A1 |
20030209746 | Horii | Nov 2003 | A1 |
20040026686 | Lung | Feb 2004 | A1 |
20040051094 | Ooishi | Mar 2004 | A1 |
20040245554 | Oh et al. | Dec 2004 | A1 |
20040248339 | Lung | Dec 2004 | A1 |
20050029502 | Hudgens | Feb 2005 | A1 |
20050093022 | Lung | May 2005 | A1 |
20050167656 | Sun et al. | Aug 2005 | A1 |
20050201182 | Osada et al. | Sep 2005 | A1 |
20050212024 | Happ | Sep 2005 | A1 |
20050215009 | Cho | Sep 2005 | A1 |
20060006472 | Jiang | Jan 2006 | A1 |
20060108667 | Lung | May 2006 | A1 |
20060110878 | Lung et al. | May 2006 | A1 |
20060118913 | Yi et al. | Jun 2006 | A1 |
20060126395 | Chen et al. | Jun 2006 | A1 |
20060175599 | Happ | Aug 2006 | A1 |
20060226409 | Burr et al. | Oct 2006 | A1 |
20060234138 | Fehlhaber et al. | Oct 2006 | A1 |
20060261321 | Happ et al. | Nov 2006 | A1 |
20060284157 | Chen et al. | Dec 2006 | A1 |
20060284158 | Lung et al. | Dec 2006 | A1 |
20060284214 | Chen | Dec 2006 | A1 |
20060284279 | Lung et al. | Dec 2006 | A1 |
20060286709 | Lung et al. | Dec 2006 | A1 |
20060286743 | Lung et al. | Dec 2006 | A1 |
20070030721 | Segal et al. | Feb 2007 | A1 |
20070037101 | Morioka | Feb 2007 | A1 |
20070072125 | Sousa et al. | Mar 2007 | A1 |
20070096248 | Philipp et al. | May 2007 | A1 |
20070108077 | Lung et al. | May 2007 | A1 |
20070108429 | Lung | May 2007 | A1 |
20070108430 | Lung | May 2007 | A1 |
20070108431 | Chen et al. | May 2007 | A1 |
20070109836 | Lung | May 2007 | A1 |
20070109843 | Lung et al. | May 2007 | A1 |
20070111429 | Lung | May 2007 | A1 |
20070115794 | Lung | May 2007 | A1 |
20070117315 | Lai et al. | May 2007 | A1 |
20070121363 | Lung | May 2007 | A1 |
20070121374 | Lung et al. | May 2007 | A1 |
20070126040 | Lung | Jun 2007 | A1 |
20070131922 | Lung | Jun 2007 | A1 |
20070131980 | Lung | Jun 2007 | A1 |
20070138458 | Lung | Jun 2007 | A1 |
20070147105 | Lung et al. | Jun 2007 | A1 |
20070154847 | Chen et al. | Jul 2007 | A1 |
20070155172 | Lai et al. | Jul 2007 | A1 |
20070158632 | Ho | Jul 2007 | A1 |
20070158633 | Lai et al. | Jul 2007 | A1 |
20070158645 | Lung | Jul 2007 | A1 |
20070158690 | Ho et al. | Jul 2007 | A1 |
20070158862 | Lung | Jul 2007 | A1 |
20070161186 | Ho | Jul 2007 | A1 |
20070173019 | Ho et al. | Jul 2007 | A1 |
20070173063 | Lung | Jul 2007 | A1 |
20070176261 | Lung | Aug 2007 | A1 |
20070257300 | Ho et al. | Nov 2007 | A1 |
20080006811 | Philipp et al. | Jan 2008 | A1 |
20080043520 | Chen | Feb 2008 | A1 |
Number | Date | Country |
---|---|---|
1568551 | Jan 2005 | CN |
WO 0045108 | Aug 2000 | WO |
0079539 | Dec 2000 | WO |
WO 0079539 | Dec 2000 | WO |
0145108 | Jun 2001 | WO |
WO 0145108 | Jun 2001 | WO |
WO-2005045847 | May 2005 | WO |
Number | Date | Country | |
---|---|---|---|
20070108431 A1 | May 2007 | US |
Number | Date | Country | |
---|---|---|---|
60736720 | Nov 2005 | US |