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Aluminum Silicon Self Aligned Gate 1 Device Cell with Narrow Word Line Pitch

IP.com Disclosure Number: IPCOM000077702D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Terman, LM: AUTHOR

Abstract

Figs. 1 and 2 show a layout of an aluminum-silicon self-aligned gate 1-device cell. The cell uses both polycrystalline silicon and metal word lines which permits the elimination of any spacing between word lines, thereby allowing minimum pitch for these word lines.

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Aluminum Silicon Self Aligned Gate 1 Device Cell with Narrow Word Line Pitch

Figs. 1 and 2 show a layout of an aluminum-silicon self-aligned gate 1- device cell. The cell uses both polycrystalline silicon and metal word lines which permits the elimination of any spacing between word lines, thereby allowing minimum pitch for these word lines.

Referring to Figs. 1 and 2, the latter shows a cross-sectional view taken along lines AA and BB of Fig. 1. The cross sections for both metal and polysilicon word lines are identical with the exception of the materials used for the word line. Thus, in Fig. 2, a bit line diffusion 1 is covered with a thick oxide 2. A thin region 3 of silicon dioxide is covered with a layer 4 of silicon nitride, both of which are disposed in underlying relationship with a polysilicon gate 5. Polysilicon gate 5 has a layer of silicon dioxide 6 formed over it and word line 7 may be of either polysilicon or metal, depending upon whether the cross section is viewed along section line AA or section line BB of Fig. 1. The steps of the process are outlined as follows: 1) Grow thick oxide on semiconductor wafer. 2) Open gate & diffusion regions (Mask #1) 3) Grow thin oxide (approximately 300 Angstroms). 4) Deposit thin silicon nitride layer (approximately 300 Angstroms). 5) Deposit polycrystalline silicon for gate 5. 6) Delineate polycrystalline layer (Mask #2). 7) Delineate silicon nitride region 4 (Mask #3). 8) Dip etch thin oxide. 9) Diffuse and regr...