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US 4,735,919 AGranted
Method of making a floating gate memory cell
AssigneeGeneral Electric Company
InventorLorenzo Faraone
Life of this patent
Estimating the term…
Abstract
A method of making a floating gate memory cell which relies on control gate to floating gate conduction to charge and discharge the floating gate. The gate oxide and inter-level dielectric thicknesses are independently controlled by using a mask which can compensate for the different substrate and floating gate oxidation rates.
Claims17
A method of making a floating gate storage device comprising the steps of:
- (a) forming a first insulating layer on a semiconductor substrate;
- (b) forming a first electroconductive layer on a portion of said first insulating layer;
- (c) forming a mask on said first electroconductive layer;
- (d) partially forming the gate oxide on areas not subtended by said mask;
- (e) removing said mask;
- (f) exposing said substrate to an oxidizing atmosphere to complete the formation of the gate oxide and to form a second insulating layer on the exposed portion of said first electroconductive layer;
- and
- (g) forming a second electroconductive layer on said second insulating layer and on a portion of said gate oxide.
5 more elements
A method of making a floating gate storage device comprising the steps of:
- (a) forming a first insulating layer on a portion of a semiconductor substrate;
- (b) forming a silicon layer on said first insulating layer;
- (c) forming a first oxidation resistant mask on said silicon layer;
- (d) oxidizing the exposed portions of said semiconductor substrate to form field oxide regions;
- (e) removing said first oxidation resistant mask;
- (f) forming a second oxidation resistant mask on a portion of said silicon layer;
- (g) removing the portions of said silicon layer which are not subtended by said second oxidation resistant mask;
- (h) partially forming the gate oxide on areas not subtended by said second oxidation resistant mask;
- (i) removing said second oxidation resistant mask;
- (j) exposing said substrate to an oxidizing atmosphere to complete the formation of said gate oxide and to form a second insulating layer on the exposed portion of said silicon layer;
- and
- (k) forming an electroconductive layer on said second insulating layer and on a portion of said gate oxide.
9 more elements
Dependencies are inferred from the claim text.