Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – Having insulated gate
Reexamination Certificate
1998-05-28
2001-05-01
Whitehead, Jr., Carl (Department: 2822)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
Having insulated gate
C438S242000, C438S248000, C438S249000, C438S270000, C438S386000, C438S391000, C438S392000
Reexamination Certificate
active
06225158
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to integrated circuit dynamic random access memories, and more particularly to trench capacitor construction.
2. Background Description
As dynamic random access memory (DRAM) cells are scaled to meet chip-size requirements for future generations, the channel length of transfer devices on the surface of the silicon substrate can no longer be scaled without degrading subthreshold leakage requirements (or retention time requirements). Process steps become complex and incompatible with standard DRAM processes, when vertical transfer devices in the DRAM cell are employed to decouple the channel length from layout ground rules.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a vertical transfer device which is built on top of a deep trench storage node and is compatible with contemporary DRAM process steps.
By integrating a robust transfer device in a Dynamic Random Access Memory (DRAM) cell having a shallow trench isolation (STI) region constructed between adjacent trench capacitor cells, having the transfer device region bound by shallow trench isolation oxide, the device channel length requirement is independent of the cell size. As an example, the inventive process may use a 256 Mb DRAM cell with 0.25 &mgr;m ground rules. The process is also applicable to other ground rules. The structures formed in the inventive process are most useful as ground rules are reduced and DRAM density is increased. The horizontal layout allows the product to be scaled with changing ground rules.
REFERENCES:
patent: 4462040 (1984-07-01), Ho et al.
patent: 4630088 (1986-12-01), Ogura et al.
patent: 4801988 (1989-01-01), Kenney
patent: 4894697 (1990-01-01), Chin et al.
patent: 4920065 (1990-04-01), Chin et al.
patent: 4941026 (1990-07-01), Temple
patent: 4977436 (1990-12-01), Tsuchiya et al.
patent: 5001526 (1991-03-01), Gotou
patent: 5071782 (1991-12-01), Mori
patent: 5073519 (1991-12-01), Rodder
patent: 5100823 (1992-03-01), Yamada
patent: 5177027 (1993-01-01), Lowrey et al.
patent: 5177576 (1993-01-01), Kimura et al.
patent: 5185646 (1993-02-01), Mizuno
patent: 5198383 (1993-03-01), Teng et al.
patent: 5216266 (1993-06-01), Ozaki
patent: 5231037 (1993-07-01), Yuan et al.
patent: 5324673 (1994-06-01), Fitch et al.
patent: 5350708 (1994-09-01), Yagishita et al.
patent: 5362665 (1994-11-01), Lu
patent: 5365097 (1994-11-01), Kenny
patent: 5414288 (1995-05-01), Fitch et al.
patent: 5480838 (1996-01-01), Mitsui
patent: 5504359 (1996-04-01), Rodder
patent: 5519236 (1996-05-01), Ozaki
patent: 5529944 (1996-06-01), Rajeevakumar
patent: 5641694 (1997-06-01), Kenny
patent: 5831301 (1998-11-01), Horak et al.
patent: 5959325 (1999-09-01), Adair et al.
patent: 8064810 (1996-03-01), None
W.F. Richardson, et al., A Trench Transistor Cross-Point DRAM Cell; IEDM, CH2252-5/85 0000-0714, 1985; pp. 714-717.
B. Wu; Pillar DRAM Cell With Dual Channels and an Underneath Trench-in-Trench Capacitor Built on SOI Structure; IBM Technical Disclosure Bulletin, vol. 36 No. 11.
S. Nakajima et al.; A Trench MOSFET With Surface Source/Drain Contacts; IEDM; CH2252-5/85/000-0200; 1985; pp. 200-203.
Furukawa Toshiharu
Hakey Mark C.
Horak David V.
Ma William H.
Mandelman Jack A.
International Business Machines - Corporation
Jr. Carl Whitehead
McGuireWoods LLP
Thomas Toniae M.
Walter, Esq. Howrd J.
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