Selective reactive ion etching of polycrystalline silicon against monocrystalline silicon

An improved Reactive Ion Etching (RIE) technique for preferentially etching polysilicon is described as is needed in Very Large Scale Integration (VLSI) using silicon technology. The etch gas is a mixture of carbon tetrafluoride (CF.sub.4) and chlorine (Cl.sub.2) diluted with inert gas. The pressure of the system is required to be in the range of about 10 to 500 milli Torr. This etch gas allows an RIE process which combines the very desirable features of selectivity (high polycrystalline silicon/monocrystalline silicon etch rate ratio) and directionality which creates substantially vertical sidewalls on the etched features.

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Description
Patent History
Patent number: T101302
Type: Grant
Filed: Mar 30, 1981
Date of Patent: Dec 1, 1981
Inventors: Lawrence E. Forget (Poughkeepsie, NY), Robert A. Gdula (Campbell Hall, NY), Joseph C. Hollis (Poughquag, NY)
Application Number: 6/249,254
Classifications
Current U.S. Class: 156/643; 156/646; 156/657; 156/662; 204/192E; 252/791
International Classification: H01L 21308;