Semiconductor constructions and methods of forming semiconductor constructions.
Memory provides data storage for electronic systems. Flash memory is one type of memory, and has numerous uses in modern computers and devices. For instance, modern personal computers may have BIOS stored on a flash memory chip. As another example, it is becoming increasingly common for computers and other devices to utilize flash memory in solid state drives to replace conventional hard drives. As yet another example, flash memory is popular in wireless electronic devices because it enables the manufacturer to support new communication protocols as they become standardized, and to provide the ability to remotely upgrade the devices for enhanced features.
A typical flash memory comprises a memory array that includes a large number of memory cells arranged in row and column fashion. The flash memory may be erased and reprogrammed in blocks.
NAND may be a basic architecture of flash memory. A NAND comprises at least one selecting device coupled in series to a serial combination of memory cells. Example NAND architecture is described in U.S. Pat. No. 7,898,850.
There is continuing goal to develop improved NAND architectures, and to develop methods of forming such NAND architectures.
In some embodiments, NAND architecture may be fabricated to comprise substantially vertical NAND strings. The fabrication may utilize line and space patterns for formation of channel regions and isolation regions, which can advantageously avoid difficulties encountered in conventional NAND fabrication processes utilizing pillars (or other high aspect ratio contacts) to support channel regions. In some embodiments, new NAND architectures may result from processes described herein. Although NAND architectures are described in some example embodiments presented herein, in other embodiments processing described herein may be utilized for fabrication of other memory, such as, for example, NOR, etc. Some example embodiments are described with reference to
Referring to
The construction 10 includes a stack 14 supported by a base 12. Stack 14 comprises alternating levels (e.g., sheets, layers, etc.) of control gate material 16 and intervening dielectric material 18. Dashed lines are provided between the stack 14 and the base 12 to indicate that there may be additional materials and/or integrated circuit structures between the base and the stack in some embodiments.
The base 12 may comprise semiconductor material, and in some embodiments may comprise, consist essentially of, or consist of monocrystalline silicon. In some embodiments, base 12 may be considered to comprise a semiconductor substrate. The term “semiconductor substrate” means any construction comprising semiconductive material, including, but not limited to, bulk semiconductive materials such as a semiconductive wafer (either alone or in assemblies comprising other materials), and semiconductive material layers (either alone or in assemblies comprising other materials). The term “substrate” refers to any supporting structure, including, but not limited to, the semiconductor substrates described above. In some embodiments, base 12 may correspond to a semiconductor substrate containing one or more materials associated with integrated circuit fabrication. Such materials may include, for example, one or more of refractory metal materials, barrier materials, diffusion materials, insulator materials, etc.
Control gate material 16 may comprise any suitable composition or combination of compositions; and in some embodiments may comprise, consist essentially of, or consist of one or more of various metals (for example, tungsten, titanium, etc.), metal-containing compositions (for instance, metal nitride, metal carbide, metal silicide, etc.), and conductively-doped semiconductor materials (for instance, conductively-doped silicon, conductively-doped germanium, etc.). For instance, in some embodiments the control gate material 16 may comprise, consist essentially of, or consist of conductively-doped silicon; such as, for example, n-type doped polycrystalline silicon.
The intervening dielectric material 18 may comprise any suitable composition; and in some embodiments may comprise, consist essentially of, or consist of silicon dioxide.
The levels of control gate material 16 may be of any suitable thickness (T1), and in some embodiments may have a thickness within a range of from about 5 nm to about 300 nm. The levels of intervening dielectric material 18 may be of any suitable thickness (T2), and in some embodiments may have a thickness within a range of from about 5 nm to about 200 nm.
The example processing described herein forms vertical NAND strings, with the number of memory cells in each string been determined by the number of control gate levels. The shown example embodiment has eight levels of control gate material 16. Other embodiments may have more or less than the shown eight levels. Accordingly, other example embodiments may have a stack with a total of 16 control gate levels, 32 control gate levels, 64 control gate levels, etc.
Referring next to
The trenches 20-22 may be formed with any suitable processing. For instance, a mask (not shown) may be formed across a top of construction 10 to define locations of the trenches, and then one or more suitable etches may be utilized to pattern the trenches through stack 14 (in some example embodiments, the etching used to form trenches 20-22 may utilize one or more of NF3, CH2F2, HBr and BCl3). Subsequently, the patterned mask may be removed to leave the illustrated construction of
The trenches 20-22 may be considered to comprise interior walls 23 (only some of which are labeled) which extend along the materials 16 and 18 of stack 14.
Referring next to
The cavities may be recessed to any suitable distance (D) into the control gate material 16, and in some embodiments may be recessed to a distance within a range of from about 5 nm to about 100 nm.
Referring to
The cell dielectric material 26 may comprise any suitable composition or combination of compositions; and in some embodiments may comprise, consist essentially of, or consist of silicon dioxide. Such silicon dioxide may be thermally grown from silicon of control gate material 16 in embodiments in which the control gate material comprises, consists essentially of, or consists of silicon. Alternatively, or additionally, at least some of the cell dielectric material may be deposited.
The cell dielectric 26 may be formed to any suitable thickness, and in some example embodiments may be formed to a thickness within a range of from about 10 Å to about 200 Å.
Referring to
The second cell dielectric material 28 may comprise any suitable composition or combination of compositions; and in some embodiments may comprise, consist essentially of, or consist of silicon nitride.
The second cell dielectric material may be formed utilizing any suitable processing, such as, for example, one or more of atomic layer deposition (ALD), chemical vapor deposition (CVD) and physical vapor deposition (PVD). It may be advantageous that the second cell dielectric material be formed conformally, as shown, and thus it may be advantageous to utilize ALD for forming such material in some embodiments.
In the shown embodiment, the intervening dielectric material 18 has surfaces 31 (only some of which are labeled) along trenches 20-22. The second cell dielectric 28 extends within cavities 24, and along surfaces 31 of dielectric material 18. In other embodiments (not shown) material 28 be removed from surfaces 31 with an appropriate etch following formation of material 28 within cavities 24.
Material 28 may be formed to any suitable thickness, and in some example embodiments may be formed to a thickness within a range of from about 50 Å to about 200 Å.
Referring to
The third cell dielectric 30 may comprise any suitable thickness, and in some example embodiments may be formed to a thickness within a range of from about 10 Å to about 100 Å.
Referring to
The charge-storage material may comprise any material suitable for retaining charge in memory cells. In some example embodiments, the charge-storage material may comprise, consist essentially of, or consist of appropriately-doped polycrystalline silicon, and may thus be utilized to form floating gates of memory cells. In some example embodiments, the charge-storage material may comprise charge-trapping material, such as, for example, silicon nitride, silicon oxynitride, conductive nanodots, etc.
The cell dielectrics 26, 28 and 30, together with the charge-storage material 32, form memory cell stacks 36 (only some of which are labeled) within the cavities 24 (the cavities are labeled in previous figures, such as, for example,
Referring to
The gate dielectric material 38 may comprise any suitable composition or combination of compositions; and in some embodiments may comprise, consist essentially of, or consist of one or more of silicon dioxide, tantalum aluminum oxide, hafnium oxide, zirconium oxide, etc. In some embodiments, the gate dielectric material may comprise a same composition as cell dielectric 26. For example, in some embodiments the gate dielectric 38 and the cell dielectric 26 may each comprise, consist essentially of, or consist of silicon dioxide.
The gate dielectric material 38 may be formed with any suitable processing including, for example, one or more of ALD, CVD and PVD. The gate dielectric material may be formed to any suitable thickness, including, for example, a thickness within a range of from about 10 Å to about 50 Å. In the shown embodiment, the gate dielectric material extends across the open ends of the containers defined by material 28, and extends across the charge-storage material 32.
In some embodiments, the charge-storage material 32 comprises silicon, and the gate dielectric material 38 comprises silicon dioxide formed by thermal oxidation of such silicon. In such embodiments, the gate dielectric material may be only along surfaces of material 32, rather than entirely along the sidewalls of the trenches.
The channel material 40 may comprise any suitable composition or combination of compositions; and in some embodiments may comprise, consist essentially of, or consist of appropriately-doped silicon (e.g., conductively-doped polysilicon). The channel material may be formed with any suitable processing, including, for example, one or more of ALD, CVD and PVD.
The channel material 40 may be considered to form panels 50-52 within the trenches 20-22, respectively. Such channel material panels extend along the direction of axis 5. In some embodiments, the channel material panels may be considered to divide stack 14 into sections. Each channel panel may form a first section on a first side of the channel panel, and a second section on a second side of the channel panel, with the second side being in opposing relation to the first side.
Referring to
The second trenches are filled with dielectric material 60. Such dielectric material may comprise any suitable composition or combination of compositions; and in some embodiments may comprise, consist essentially of, or consist of silicon dioxide. The dielectric material 60 may be considered to form dielectric material panels 104-107 within the trenches 54-57.
The third trenches are filled with dielectric material 80. Such dielectric material may comprise a suitable composition or combination of compositions; and in some embodiments may comprise, consist essentially of, or consist of silicon dioxide. The dielectric material 80 may be considered to form dielectric material panels 108-125 within the trenches 61-78. In some embodiments, the dielectric material panels 104-107 may be referred to as first dielectric material panels, and the dielectric material panels 108-125 may be referred to as second dielectric material panels.
In the shown embodiment, the second dielectric material panels are thicker than the first dielectric material panels. In other embodiments, the first and second dielectric material panels may be the same thicknesses as one another, or the first dielectric material panels may be thicker than the second dielectric material panels.
In some embodiments, the trenches 54-57 may be formed prior to the trenches 61-78; in other embodiments the trenches 61-78 may be formed prior to the trenches 54-57; and in yet other embodiments the trenches 61-78 may be formed simultaneously with the trenches 54-57. Further, in some embodiments the trenches 54-57 may be filled with dielectric material 60 prior to filling the trenches 61-78 (and even prior to forming the trenches 61-78 in some embodiments); in other embodiments the trenches 61-78 may be filled with dielectric material 80 prior to filling the trenches 54-57 (and even prior to forming the trenches 54-57 in some embodiments); and in some embodiments the trenches 54-57 may be filled simultaneously with the filling of the trenches 61-78. In embodiments in which the trenches 54-57 are filled simultaneously with the trenches 61-78, all of the trenches 54-57 and 61-78 may be filled with the same material as one another. In such embodiments, the material filling trenches 54-57 and 61-78 may, for example, comprise, consist essentially of, or consist of silicon dioxide.
Although the shown embodiment has the trenches 20-22 formed and filled with channel material prior to forming and filling the second trenches 54-57; in other embodiments, the trenches 54-57 may be formed and filled prior to forming and filling the trenches 20-22. In such other embodiments, the dielectric material panels 104-107 may be considered to be formed prior to the channel material panels 50-52.
In some embodiments, the first dielectric material panels 104-107 may be considered to divide stack 14 into a plurality of slices 150-152, with the individual slices extending along a first direction defined by axis 5 (as shown in the top view of
The second dielectric material panels 108-125 extend along a second direction defined by axis 7, with such second direction being substantially orthogonal to the first direction of axis 5. The second dielectric material panels 108-125 are in a many-to-one correspondence with each of slices 150-152. The second dielectric material panels 108-125 extend through the channel material panels, but only extend partially across the slices so that there are regions 154 of the slices (labeled in
The dielectric material panels 108-125 divide the channel material panels 50-52 into a plurality of segments 160 (labeled in
The memory cell stacks 36 are between the control gate material 16 and the channel material 40, with the memory cell stacks being incorporated into memory cells formed along the levels of the control gate material 16. In some embodiments, memory cell stacks may be considered to be paired across a channel region. For instance, two memory cell stacks are labeled as cell stacks 36a and 36b in
In some embodiments, memory cell stack 36a may be part of a different string of memory cells than memory cell stack 36b, and in other embodiments the memory cell stacks 36a and 36b may be part of the same memory cell string as one another. For instance, in some embodiments memory cell stack 36a may be part of a memory cell string which includes only the memory cells directly above and directly below the stack 36a; and memory cell stack 36b may be part of a memory cell string which includes only the memory cells directly above and below the stack 36b. Thus, the portion of the channel material panel 50 shown in
As another example, in some embodiments the memory cell stacks 36 at a common level along a channel are electrically coupled to one another and are thereby paired to form a single memory cell (e.g., a NAND memory cell) from two adjacent memory cell stacks. Thus, memory cell stacks 36a and 36b may be part of a single memory cell in some embodiments. Such embodiments may comprise ohmically connecting charge-storage material 32 on one side of a channel material panel with charge-storage material on an opposing side of the channel material panel; such as, for example, ohmically connecting charge-storage material of memory stack 36a with charge-storage material of memory stack 36b.
Regardless of whether adjacent cell stacks are coupled to one another to form a single memory cell or not, the charge storage materials 32 of the memory cells described above may comprise floating gates or charge-trapping materials; and thus the memory cells may, for example, correspond to SONOS configurations, TaNOS configurations, etc.
Referring to
The memory discussed above may be incorporated into electronic systems. Such electronic systems may be used in, for example, memory modules, device drivers, power modules, communication modems, processor modules, and application-specific modules, and may include multilayer, multichip modules. The electronic systems may be any of a broad range of systems, such as, for example, clocks, televisions, cell phones, personal computers, automobiles, industrial control systems, aircraft, etc.
The particular orientation of the various embodiments in the drawings is for illustrative purposes only, and the embodiments may be rotated relative to the shown orientations in some applications. The description provided herein, and the claims that follow, pertain to any structures that have the described relationships between various features, regardless of whether the structures are in the particular orientation of the drawings, or are rotated relative to such orientation.
The cross-sectional views of the accompanying illustrations only show features within the planes of the cross-sections, and do not show materials behind the planes of the cross-sections in order to simplify the drawings.
When a structure is referred to above as being “on” or “against” another structure, it can be directly on the other structure or intervening structures may also be present. In contrast, when a structure is referred to as being “directly on” or “directly against” another structure, there are no intervening structures present. When a structure is referred to as being “connected” or “coupled” to another structure, it can be directly connected or coupled to the other structure, or intervening structures may be present. In contrast, when a structure is referred to as being “directly connected” or “directly coupled” to another structure, there are no intervening structures present.
Some embodiments include a semiconductor construction which comprises a stack containing alternating levels of control gate material and intervening dielectric material. A channel material panel extends through the stack along a first direction. The channel material panel divides the stack into a first section on a first side of the channel material panel and a second section on a second side of the channel material panel. The second side is in opposing relation to the first side. Memory cell stacks are between the channel material panel and the control gate material on both sides of the channel material panel. The memory cell stacks comprise cell dielectric material shaped as containers having open ends pointing toward the channel material panel, and comprise charge-storage material within the containers. Electrically insulative panels extend through the channel material panel and the stack, and sub-divide the channel material panel into a plurality of segments. The channel material panel extends along a first direction, and the electrically insulative panels extend along a second direction substantially orthogonal to the first direction.
Some embodiments include a semiconductor construction which comprises a stack containing alternating control gate material and intervening dielectric material. First dielectric material panels extend through the stack. The first dielectric material panels divide the stack into a plurality of slices which extend along a first direction. Channel material panels extend along the first direction. Individual channel material panels extend approximately along a center of each slice. A plurality of second dielectric material panels extend through the stack and along a second direction substantially orthogonal to the first direction. The second dielectric material panels are in a many-to-one correspondence with each slice, extend through the channel material panels, and extend only partially across the slices. Memory cell stacks are between the channel material panels and the control gate material. The memory cell stacks comprise cell dielectric material shaped as containers having open ends pointing toward the channel material panels, and comprise charge-storage material within the containers.
Some embodiments include a method of forming a semiconductor construction. A stack is formed, with the stack comprising alternating control gate material and intervening dielectric material. First trenches are formed within the stack and such first trenches extend along a first direction. The control gate material is recessed along interior walls of the first trenches to form a plurality of cavities along the interior walls. The cavities are bounded on top and bottom by the intervening dielectric material, and on one side by the control gate material. Memory cell stacks are formed within the cavities. The memory cell stacks comprise cell dielectric material shaped as containers and having open ends pointing away from the sides of the cavities bounded by the control gate material. The memory cell stacks also comprise charge-storage material within the containers. After the memory cell stacks are formed, channel material panels are formed within the first trenches. The channel material panels extend along the first direction of the first trenches. Second trenches are formed within the stack and extend along the first direction. First dielectric material panels are formed within the second trenches. Third trenches are formed within the stack and channel material panels, with the third trenches extending along a second direction substantially orthogonal to the first direction. Second dielectric material panels are formed within the third trenches.
In compliance with the statute, the subject matter disclosed herein has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the claims are not limited to the specific features shown and described, since the means herein disclosed comprise example embodiments. The claims are thus to be afforded full scope as literally worded, and to be appropriately interpreted in accordance with the doctrine of equivalents.
This patent resulted from a divisional of U.S. patent application Ser. No. 13/675,933 which was filed Nov. 13, 2012, now U.S. Pat. No. 9,178,077, which is hereby incorporated by reference.
Number | Name | Date | Kind |
---|---|---|---|
6057193 | Wang et al. | May 2000 | A |
6063666 | Chang et al. | May 2000 | A |
6143604 | Chieng et al. | Nov 2000 | A |
6180454 | Chang et al. | Jan 2001 | B1 |
6274471 | Huang | Aug 2001 | B1 |
6353242 | Watanabe et al. | Mar 2002 | B1 |
6661691 | Fricke et al. | Dec 2003 | B2 |
6803318 | Qiao et al. | Oct 2004 | B1 |
7112488 | Helm et al. | Sep 2006 | B2 |
7112490 | Hong et al. | Sep 2006 | B1 |
7196004 | Lee et al. | Mar 2007 | B2 |
7419895 | Lindsay | Sep 2008 | B2 |
7713819 | Okajima | May 2010 | B2 |
7790360 | Alapati et al. | Sep 2010 | B2 |
7829935 | Makihara et al. | Nov 2010 | B2 |
7898856 | Aritome | Mar 2011 | B2 |
7906818 | Pekny | Mar 2011 | B2 |
7968406 | Ramaswamy et al. | Jun 2011 | B2 |
8148216 | Arai et al. | Apr 2012 | B2 |
8183110 | Ramaswamy et al. | May 2012 | B2 |
8187938 | Lim et al. | May 2012 | B2 |
8207570 | Alapati et al. | Jun 2012 | B2 |
8228743 | Min et al. | Jul 2012 | B2 |
8237213 | Liu | Aug 2012 | B2 |
8278695 | Kidoh et al. | Oct 2012 | B2 |
8283205 | Pagaila et al. | Oct 2012 | B2 |
8288811 | Ramaswamy et al. | Oct 2012 | B2 |
8431456 | Alapati et al. | Apr 2013 | B2 |
8437192 | Lung et al. | May 2013 | B2 |
8450791 | Alsmeier | May 2013 | B2 |
8507976 | Joo | Aug 2013 | B2 |
8969153 | Lee et al. | Mar 2015 | B2 |
9041090 | Simsek-Ege et al. | May 2015 | B2 |
20030201500 | Furukawa et al. | Oct 2003 | A1 |
20050200026 | Liaw | Sep 2005 | A1 |
20070004140 | Jang et al. | Jan 2007 | A1 |
20070004141 | Kim et al. | Jan 2007 | A1 |
20070048989 | Ahn et al. | Mar 2007 | A1 |
20080009113 | Shimizu | Jan 2008 | A1 |
20080179659 | Enda et al. | Jul 2008 | A1 |
20080220600 | Alapati et al. | Sep 2008 | A1 |
20090117725 | Sun | May 2009 | A1 |
20090230454 | Pekny | Sep 2009 | A1 |
20090289297 | Kim et al. | Nov 2009 | A1 |
20090296476 | Shin et al. | Dec 2009 | A1 |
20090310425 | Sim et al. | Dec 2009 | A1 |
20100155813 | Murata et al. | Jun 2010 | A1 |
20100171162 | Katsumata et al. | Jul 2010 | A1 |
20100208503 | Kuo | Aug 2010 | A1 |
20100258852 | Lim et al. | Oct 2010 | A1 |
20100276743 | Kuniya et al. | Nov 2010 | A1 |
20100295114 | Alapati et al. | Nov 2010 | A1 |
20110019486 | Jang et al. | Jan 2011 | A1 |
20110024816 | Moon et al. | Feb 2011 | A1 |
20110031550 | Komori et al. | Feb 2011 | A1 |
20110032772 | Aritome | Feb 2011 | A1 |
20110147823 | Kuk et al. | Jun 2011 | A1 |
20110149656 | Tang et al. | Jun 2011 | A1 |
20110177661 | Song et al. | Jul 2011 | A1 |
20110180865 | Ramaswamy | Jul 2011 | A1 |
20110193153 | Higuchi et al. | Aug 2011 | A1 |
20110241098 | Park et al. | Oct 2011 | A1 |
20110291172 | Hwang et al. | Dec 2011 | A1 |
20110316064 | Kim et al. | Dec 2011 | A1 |
20120001249 | Alsmeier et al. | Jan 2012 | A1 |
20120012921 | Liu | Jan 2012 | A1 |
20120068247 | Lee et al. | Mar 2012 | A1 |
20120086072 | Yun et al. | Apr 2012 | A1 |
20120098050 | Shim et al. | Apr 2012 | A1 |
20120119285 | Yang | May 2012 | A1 |
20120135583 | Jang et al. | May 2012 | A1 |
20120175697 | Hall et al. | Jul 2012 | A1 |
20120184078 | Kiyotoshi | Jul 2012 | A1 |
20120193596 | Nakazawa | Aug 2012 | A1 |
20120205722 | Lee et al. | Aug 2012 | A1 |
20120211822 | Lim et al. | Aug 2012 | A1 |
20120211823 | Lim et al. | Aug 2012 | A1 |
20120217564 | Tang et al. | Aug 2012 | A1 |
20120220088 | Alsmeier | Aug 2012 | A1 |
20120231593 | Joo et al. | Sep 2012 | A1 |
20120238077 | Alapati et al. | Sep 2012 | A1 |
20120241842 | Matsuda | Sep 2012 | A1 |
20120329224 | Kong et al. | Dec 2012 | A1 |
20130087843 | Han | Apr 2013 | A1 |
20130193503 | Lee et al. | Aug 2013 | A1 |
20140008714 | Makala et al. | Jan 2014 | A1 |
20140131784 | Davis | May 2014 | A1 |
20140162418 | Keshav et al. | Jun 2014 | A1 |
20140191306 | Hopkins | Jul 2014 | A1 |
20140191340 | Thimmegowa et al. | Jul 2014 | A1 |
20140203344 | Hopkins et al. | Jul 2014 | A1 |
20140217488 | Thimmegowa et al. | Aug 2014 | A1 |
20140339621 | Ramaswamy | Nov 2014 | A1 |
20140339624 | Ramaswamy | Nov 2014 | A1 |
Number | Date | Country |
---|---|---|
10-2011-0000487 | Jan 2011 | KR |
10-2011-0120654 | Nov 2011 | KR |
10-2012-0113596 | Oct 2012 | KR |
200845125 | Nov 2008 | TW |
PCTUS2013063302 | May 2015 | WO |
PCTUS2014011228 | Aug 2015 | WO |
Entry |
---|
WO PCT/US2013/063302 Search Rept., Jan. 15, 2014, Micron Technology, Inc. |
WO PCT/US2013/063302 Writ. Opin., Jan. 15, 2014, Micron Technology, Inc. |
WO PCT/US2014/011228 Search Rept., Apr. 30, 2014, Micron Technology, Inc. |
WO PCT/US2014/011228 Writ. Opin., Apr. 30, 2014, Micron Technology, Inc. |
TW TW 102138545 Search Rept Trans, Apr. 20, 2015, Micron Technology, Inc. |
Wang et al. “Electrical Properties of Crystalline YSZ Films on Silicon as Alternative Gate Dielectrics”, Semiconductor Science & Technology 16, 2001, United Kingdom, pp. L13-L16. |
Number | Date | Country | |
---|---|---|---|
20160071878 A1 | Mar 2016 | US |
Number | Date | Country | |
---|---|---|---|
Parent | 13675933 | Nov 2012 | US |
Child | 14930504 | US |