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Compensation Method for Fabricating Dual Polarity Polycrystalline Silicon Gates for CMOS Integrated Circuits

IP.com Disclosure Number: IPCOM000044955D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 64K

Publishing Venue

IBM

Related People

Bassous, E: AUTHOR [+3]

Abstract

This publication relates to an improved fabrication process wherein P and N/+/ polycrystalline silicon (poly-Si) gates are fabricated on the same structure using the same number of masks as single-polarity poly-Si devices.

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Compensation Method for Fabricating Dual Polarity Polycrystalline Silicon Gates for CMOS Integrated Circuits

This publication relates to an improved fabrication process wherein P and N/+/ polycrystalline silicon (poly-Si) gates are fabricated on the same structure using the same number of masks as single-polarity poly-Si devices.

The compensation method described herein is for the fabrication of dual-polarity poly-Si gate CMOS structures. Its advantage lies in the use of the same number of lithographic masking levels as conventional single-polarity gate structures. The starting point of the proposed process is shown in Fig. 1A. It represents a typical cross-section of a CMOS structure after Ion implantation of the deep n-type well and p+ field, and growth of the recessed oxide. The sequence of steps concerned with the fabrication of the p+ and n+ poly-Si gates is illustrated in Figs. 1A, 1B, 1C and D and are described as follows in Steps 1, 2, 3 and 4, respectively. Conventional processing methods are used and minor variations or options are shown in parentheses.

Step 1 (Fig. 1A) - Deposit approx. 300 nm p-type poly-Si - Apply resist - Define gate pattern - RIE 90% p-type poly-Si, strip resist
Alternatively (RIE 100% poly-Si,

strip resist,

deposit approx.30 nm pol - Grow approx.30 nm SiO(2) Step 2 (Fig. 1B) - Apply resist - Define source and drain (n-channel) - RIE SiO(2) (dip etch) - Ion implant As

Step 3 (Fig. 1C) - Strip resist - POC1(3) doping - (Dip etch PSG...