Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Reexamination Certificate
2002-01-07
2004-12-28
Whitehead, Jr., Carl (Department: 2813)
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
Reexamination Certificate
active
06835975
ABSTRACT:
TECHNICAL FIELD
This invention relates to methods of depositing aluminum nitride comprising layers over semiconductor substrates, to methods of forming DRAM circuitry, to DRAM circuitry, to methods of forming field emission devices, and to field emission devices.
BACKGROUND OF THE INVENTION
This invention was principally motivated in addressing problems and improvements in dynamic random access memory (DRAM) and in field emission devices, such as displays.
As DRAMs increase in memory cell density, there is a continuing challenge to maintain sufficiently high storage capacitance despite decreasing cell area. Additionally, there is a continuing goal to further decrease cell area. One principal way of increasing cell capacitance is through cell structure techniques. Such techniques include three-dimensional cell capacitors, such as trenched or stacked capacitors. Yet as feature size continues to become smaller and smaller, development of improved materials for cell dielectrics as well as the cell structure are important. The feature size of 256 Mb DRAMs will be on the order of 0.25 micron or less, and conventional dielectrics such as SiO
2
and Si
3
N
4
might not be suitable because of small dielectric constants. Highly integrated memory devices, such as 256 Mbit DRAMs and beyond, are expected to require a very thin dielectric film for the 3-dimensional capacitor of cylindrically stacked or trench structures. To meet this requirement, the capacitor dielectric film thickness will be below 2.5 nm of SiO
2
equivalent thickness.
Field emission displays are one type of field emission device, and are utilized in a variety of display applications. Conventional field emission displays include a cathode plate having a series of emitter tips fabricated thereon. The tips are configured to emit electrons toward a phosphor screen to produce an image. The emitters are typically formed from an emitter material such as conductive polysilicon, molybdenum, or aluminum. Multiple emitters are typically utilized to excite a single pixel. For example, 120 emitters may be used for a single pixel. Individual pixels contain a deposited one of red, green, or blue phosphor.
Clarity, or resolution, of a field emission display is a function of a number of factors, including emitter tip sharpness. Specifically, sharper emitter tips can produce higher resolution displays than less sharp emitter tips. One adverse phenomenon impacting emitter tip sharpness is undesired native oxidation of the emitter tips during fabrication if exposed to an oxidizing atmosphere, such as room air. Such oxidation consumes material of the tips in forming an oxide and reduces sharpness and therefore clarity.
SUMMARY OF INVENTION
The invention is a method of depositing an aluminum nitride comprising layer over a semiconductor substrate, a method of forming DRAM circuitry, DRAM circuitry, a method of forming a field emission device, and a field emission device. In one aspect, a method of depositing an aluminum nitride comprising layer over a semiconductor substrate includes positioning a semiconductor substrate within a chemical vapor deposition reactor. Ammonia and at least one compound of the formula R
3
Al, where “R” is an alkyl group or a mixture of alkyl groups, are fed to the reactor while the substrate is at a temperature of about 500° C. or less and at a reactor pressure from about 100 mTorr to about 725 Torr effective to deposit a layer comprising aluminum nitride over the substrate at such temperature and reactor pressure. In one aspect, such layer is utilized as a cell dielectric layer in DRAM circuitry. In one aspect, such layer is deposited over emitters of a field emission display.
In one aspect, the invention includes DRAM circuitry having an array of word lines forming gates of field effect transistors and an array of bit lines. Individual field effect transistors have a pair of source/drain regions. A plurality of memory cell storage capacitors are associated with the field effect transistors. Individual storage capacitors have a first capacitor electrode in electrical connection with one of a pair of source/drain regions of one of the field effect transistors and a second capacitor electrode. A capacitor dielectric region is received intermediate the first and second capacitor electrodes, with the region comprising aluminum nitride, and the other of the pair of source/drain regions of the one field effect transistor being in electrical connection with one of the bit lines.
In one aspect, a field emission device includes an electron emitter substrate including emitters having at least a partial covering comprising an electrically insulative material other than an oxide of silicon, with aluminum nitride being but one example. An electrode collector substrate is spaced from the electron emitter substrate.
REFERENCES:
patent: 5062133 (1991-10-01), Melrose
patent: 5183684 (1993-02-01), Carpenter
patent: 5208848 (1993-05-01), Pula
patent: 5351276 (1994-09-01), Doll, Jr. et al.
patent: 5356608 (1994-10-01), Gebhardt
patent: 5386459 (1995-01-01), Veeneman et al.
patent: 5390241 (1995-02-01), Bales et al.
patent: 5392345 (1995-02-01), Otto
patent: 5404400 (1995-04-01), Hamilton
patent: RE35050 (1995-10-01), Gibbs et al.
patent: 5459780 (1995-10-01), Sand
patent: 5463685 (1995-10-01), Gaechter et al.
patent: 5536193 (1996-07-01), Kumar
patent: 5573742 (1996-11-01), Gebhardt
patent: 5599732 (1997-02-01), Razeghi
patent: 5605858 (1997-02-01), Nishioka et al.
patent: 5650361 (1997-07-01), Radhakrishnan
patent: 5656113 (1997-08-01), Ikeda et al.
patent: 5682386 (1997-10-01), Arimilli et al.
patent: 5687112 (1997-11-01), Ovshinsky
patent: 5689553 (1997-11-01), Ahuja et al.
patent: 5709928 (1998-01-01), Ikeda et al.
patent: 5767578 (1998-06-01), Chang et al.
patent: 5773882 (1998-06-01), Iwasaki
patent: 5783483 (1998-07-01), Gardner
patent: 5783716 (1998-07-01), Baum et al.
patent: 5786259 (1998-07-01), Kang
patent: 5786635 (1998-07-01), Alcoe et al.
patent: 5852303 (1998-12-01), Cuomo et al.
patent: 5977582 (1999-11-01), Fleming et al.
patent: 5977698 (1999-11-01), Lee
patent: 6072211 (2000-06-01), Miller et al.
patent: 6128293 (2000-10-01), Pfeffer
patent: 6181056 (2001-01-01), Yaniv et al.
patent: 6218293 (2001-04-01), Kraus et al.
patent: 6218771 (2001-04-01), Berishev et al.
patent: 6285050 (2001-09-01), Emma et al.
patent: 6294420 (2001-09-01), Tsu et al.
patent: 6307775 (2001-10-01), Forbes et al.
patent: 6358810 (2002-03-01), Dornfest et al.
patent: 6372530 (2002-04-01), Lee
patent: 6459096 (2002-10-01), Razeghi
patent: 401230779 (1989-09-01), None
Herng Liu, “The Surface Cheistry of Aluminum Nitride MOCVD on Alumina Using Trimethylaluminum and Ammonia As Precursors”, Surface Science 320, pp. 145-160, 1994.*
Armas, B., et al., “Chemical Vapor Deposition Of Si3N4and AlN on Carbon Fibers”,Chemical Vapor Deposition 1987, The Electrochemical Society, Inc., Proceedings vol. 87-8, pp. 1060-1069 (1987).
Suzuki, M., et al., “CVD Of Polycrystalline Aluminum Nitride”,Chemical Vapor Deposition 1987, The Electrochemical Society, Inc., Proceedings vol. 87-8, pp. 1089-1097 (1987).
Kobayashi, N., et al.,Improved 2DEG Mobility In Selectively Doped GaAs/N-AlGaAs Grown by MOCVD Using Triethyl Organometallic Compounds, Musashino Elect. Comm. Lab., Nippon Tel & Telegraph, Japan, 2 Pages, (Sep. 10, 1984).
Pierson, Hugh O.,Handbook Of Chemical Vapor Deposition(CVD), Noyes Publications, N.J., pp. 216-219 (undated).
CVD OF Nonmetals, Editor: William S. Rees, Jr., pp. 301-307 (1996).
C. Jimenez et al.,Preparation of aluminum nitride films by low pressure organometallic chemical vapor deposition, 76-77 Surface and Coatings Technology 372-376 (1995).
H. Liu et al.,The surface chemistry of aluminum nitride MOCVD on alumina using trimethylaluminum and ammonia as precursors, 320 Surface Science 145-160 (1994).
U.S. Appl. No. 09/191,294, filed Nov. 1998, Brenda D. Kraus et al.
Kraus Brenda D.
Lane Richard H.
Dolan Jennifer M
Jr. Carl Whitehead
Wells St. John P.S.
LandOfFree
DRAM circuitry having storage capacitors which include... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with DRAM circuitry having storage capacitors which include..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and DRAM circuitry having storage capacitors which include... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3274133