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US 7,001,810 B2Granted
Floating gate nitridation
AssigneeProMOS Technologies Inc.
InventorsZhong Dong, Chuck Jang, Ching-Hwa Chen
Life of this patent
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Abstract
The floating gate, or the oxide between the floating and control gates, or both are nitrided before the control gate layer is deposited.
Claims19
A method for manufacturing an integrated circuit comprising a nonvolatile memory, the method comprising:
- (a) forming a conductive first layer containing primarily silicon, the first layer being to provide one or more floating gates for the nonvolatile memory;
- (b) nitriding a silicon-containing surface of the first layer with a low temperature, low energy, surface nitriding process such as Remote Plasma Nitridation (RPN) or Decoupled Plasma Nitridation (DPN) so as to incorporate nitrogen atoms into said silicon-containing surface of the first layer at relatively low temperature and relatively low energy;
- (c) subjecting the nitrided surface to a thermally oxidizing atmosphere so as to thereby form a thermally-grown silicon oxide at the nitrided surface, the combination of the thermally-grown silicon oxide and incorporated nitrogen atoms defining at least part of a first dielectric of the nonvolatile memory;
- and
- (d) forming a conductive second layer separated by the first dielectric from conductive material of the first layer, the conductive second layer providing one or more control gates for the nonvolatile memory.
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A method of manufacturing a nonvolatile memory cell within a monolithically integrated circuit, the method comprising:
- (a) forming a tunneling dielectric layer on a semiconductive substrate;
- (b) forming a floating gate layer on said tunneling dielectric layer, the floating gate layer having a top surface composed primarily of conductive silicon;
- (c) surface nitridating said top surface of the floating gate layer with a low temperature, low energy process such as Remote Plasma Nitridation (RPN) or Decoupled Plasma Nitridation (DPN) so as to incorporate nitrogen atoms into said top surface of the floating gate layer at relatively low temperature and relatively low energy;
- and
- (d) subjecting the nitrided top surface to a thermally oxidizing atmosphere so as to thereby form a combination of thermally-grown silicon oxide and surface incorporated and thermally treated nitrogen atoms at the nitrided and thermally oxidized top surface of the floating gate layer.
2 more elements
Dependencies are inferred from the claim text.