( 1 of 115 ) |
United States Patent | 6,294,813 |
Forbes ,   et al. | September 25, 2001 |
A method and structure for textured surfaces in non volatile floating gate tunneling oxide (FLOTOX) devices, e.g. FLOTOX transistors, are provided. The present invention capitalizes on using "self-structured masks" and a controlled etch to form nanometer scale microtip arrays to form the textured surfaces. The present invention further employs atomic layer epitaxy (ALE) to create a very conformal tunnel oxide layer which complements the nanometer scale microtip arrays. The resulting structure provides a higher tunneling current than currently exists in FLOTOX technology. The improved tunneling currents at low voltages can make these FLOTOX devices suitable for replacing DRAMS.
Inventors: | Forbes; Leonard (Corvallis, OR); Geusic; Joseph E. (Berkeley Heights, NJ) |
Assignee: | Micron Technology, Inc. (Boise, ID) |
Appl. No.: | 504496 |
Filed: | February 15, 2000 |
Current U.S. Class: | 257/321; 257/315; 257/317; 365/185.28 |
Intern'l Class: | H01L 029/788 |
Field of Search: | 257/315,317,321,322 438/211,257 365/185.26,185.28 |
4486769 | Dec., 1984 | Simko | 257/317. |
4757360 | Jul., 1988 | Faraone et al. | 257/317. |
4947221 | Aug., 1990 | Stewart et al. | 257/316. |
5089867 | Feb., 1992 | Lee | 257/316. |
5278087 | Jan., 1994 | Jenq | 438/594. |
5304505 | Apr., 1994 | Hazani | 438/264. |
5429966 | Jul., 1995 | Wu et al. | 438/594. |
5502668 | Mar., 1996 | Shimoji et al. | 365/185. |
5544103 | Aug., 1996 | Lambertson | 365/185. |
5631482 | May., 1997 | Hong | 257/326. |
5888870 | Mar., 1999 | Gardner et al. | 438/261. |
5963480 | Oct., 1999 | Harari | 365/185. |
6043124 | Mar., 2000 | Wu | 438/260. |
Fong, Y., et al., "Oxides Grown on Textured Single-Crystal Silicon-Dependence on Process and Application in EEPROMs", IEEE Transactions on Electron Devices, 37(3), pp. 583-590, (Mar. 1990). Gasser, W., et al., "Quasi-monolayer Deposition of Silicon Dioxide", This Solid Films (250), pp. 213-218, (1994). Geusic, J., et al., "Structured Silicon Surfaces and Tunnel Oxides for Flash Memory Devices", Micron Disclosure, (Sep. 25, 1997). Hao, M.Y., et al., "Electrical Characteristics of Oxynitrides Grown on Textured Single-Crystal Silicon", Appl. Phys. Lett., 60, 445-447, (Jan. 1992). Klaus, et al., "Atomic Layer Controlled Growth of SiO2 Films Using Binary Reaction Sequence Chemistry", Applied Physics Lett. 70 (9), 1092-94, (Mar. 3, 1997). Ott, A.W., et al., "Al303 Thin Film Growth on Si (100) Using Binary Reaction Sequence Chemistry", Thin Solid Films, vol. 292, 135-44, (1997). Suntola, T., "Atomic Layer Epitaxy", Handbook of Crystal Growth 3, Thin Films of Epitaxy, Part B: Growth Mechanics and Dynamics, Elsevier, Amsterdam, 601-63, (1994). Wang, P.W., et al., "Excellent Emission Characteristics of Tunneling Oxides Formed Using Ultrathin Silicon Films for Flash Memory Devices", Japanese Journal of Applied Physics, 35, 3369-3373, (Jun. 1996). Anderson et al., Evidence for Surface Asperity Mechanism of Conductivity in Oxide Grown on Polycrystalline Silicon, J. of App. Phys., Vo. 48, Iss. 11, pp. 4834-4836 (abstract only provided), Nov. 1977. |