Alternate method and structure for improved floating gate tunneling devices

Patent 6025627 Issued on February 15, 2000. Estimated Expiration Date:

May 29, 2018. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Floating gate memory device with facing asperities on floating and control gates
Patent #: 4757360
Issued on: 07/12/1988
Inventor: Faraone

Memory cell for a dense EPROM
Patent #: 4947221
Issued on: 08/07/1990
Inventor: Stewart, et al.

Method of fabricating a textured tunnel oxide for EEPROM applications Patent #: 5429966
Issued on: 07/04/1995
Inventor: Wu, et al.

Inventors

Application

No. 087473 filed on 05/29/1998

US Classes:

257/321, With thin insulator region for charging or discharging floating electrode by quantum mechanical tunneling257/316, With additional contacted control electrode257/319, Plural additional contacted control electrodes257/E21.209, Making electrode structure comprising conductor-insulator-conuctor-insulator-semiconductor, e.g., gate stack for non-volatile memory (EPO)257/E29.162, Insulating materials for IGFET (EPO)257/E29.304Charging by tunneling of carriers (e.g., Fowler-Nordheim tunneling) (EPO)

Examiners

Primary: Saadat, Mahshid
Assistant: Eckert, II, George C.

Attorney, Agent or Firm

International Class

H01L 029/788

Abstract

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.

Other References

Fong, Y., et al., "Oxides Grown on Textured Single-Crystal Silicon--Dependence on Process and Application in EEPROMs", IEEE Transactions on Electron Devices, 37, 583-590, (Mar. 1990)
Gasser, W., et al., "Quasi-monolayer Deposition of Silicon Dioxide", This Solid Films (250), pp. 213-218, (1994)
Guesic, 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 Let. 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 Characteristic of Tunneling Oxides Formed Using Ultrathin Silicon Films for Flash Memory Devices", Japanese Journal of Applied Physics, 35, 3369-3373, (Jun. 1996