Method of fabricating MOS field effect transistors
First Claim
1. A method of fabricating a semiconductor device (20) having a pair of spaced-apart source and drain contact electrodes (12.1, 12.2) contacting spaced-apart surface areas of source and drain regions (10.1, 10.2), respectively, located at a top surface of a semiconductor body (10) and having a gate oxide layer (10.3) grown on a first portion of the said top surface located between said apart areas characterized by the step of forming a sidewall insulating layer (15.1, 15.2) on an exposed mutually opposing sidewall edge surface of each of the contact electrodes (12.1, 12.2), followed by the step of thermally growing the gate oxide layer (10.3).
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Abstract
A method for making a MOSFET device (20) in a semiconductor body (10) includes the step of forming source and drain contact electrodes (12.1, 12.2) prior to growth of the gate oxide (10.3) and after formation of a high conductivity surface region (10.5). The exposed mutually opposing sidewall edges of each of the contact electrodes (12.1, 12.2) are coated with a sidewall silicon dioxide layer (15.1, 15.2), and the then exposed surface of the semiconductor body (10) between these sidewalls is etched to depth beneath the high conductivity surface region (10.5) in order to separate it into the source and drain regions (10.1, 10.2).
Formation of the high conductivity region may be omitted by using Schottky barrier or impurity doped material for the contact electrodes (12.1, 12.2).
126 Citations
20 Claims
- 1. A method of fabricating a semiconductor device (20) having a pair of spaced-apart source and drain contact electrodes (12.1, 12.2) contacting spaced-apart surface areas of source and drain regions (10.1, 10.2), respectively, located at a top surface of a semiconductor body (10) and having a gate oxide layer (10.3) grown on a first portion of the said top surface located between said apart areas characterized by the step of forming a sidewall insulating layer (15.1, 15.2) on an exposed mutually opposing sidewall edge surface of each of the contact electrodes (12.1, 12.2), followed by the step of thermally growing the gate oxide layer (10.3).
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5. A method for making a MOSFET device (20) comprising the steps of:
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(a) forming a pair of spaced-apart contact electrodes (12.1, 12.2) whose top surfaces are coated with an intermediate insulating layer (13,
14), said electrodes (12.1, 12.2) being essentially metal, metal-silicide, or silicon rich metal-silicide, and said electrodes making contact with spaced-apart areas of a top surface of a semiconductor body (10);(b) forming sidewall edge insulating layers (15.1, 15.2) on exposed mutually opposed sidewall edges of each of said contact electrodes (12.1, 12.2) contiguous with said spaced-apart areas of contact; (c) forming a recess in the body (10) at the top surface thereof located between said sidewall insulating layers (15.1, 15.2) to at least a predetermined depth; (d) forming a gate oxide layer (10.3) coating said recess; and (e) forming a gate electrode layer (16.3) covering both said gate oxide layer (10.3) and each of the sidewall insulating layers (15.1, 15.2). - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method of making a MOSFET device comprising the steps of:
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(a) forming a pair of spaced-apart field oxide layer portions (11) at a major surface of a semiconductive silicon body (10); (b) introducing conductivity type determining impurities into the body to form a doped region of predetermined depth (10.5) of the body located contiguous with the major surface thereof in the space between the field oxide layer portions (11), said doped region (10.5) being of opposite type and higher conductivity as compared with the conductivity of the bulk of body (
10);(c) depositing a contact electrode layer (12) essentially of metal, metal-silicide, or silicon rich metal-silicide on said field oxide layers (11) and on the exposed portions of said major surface of the body (10) in the space between the field oxide layer portions (11); (d) forming an intermediate insulating layer (13,
14) on said contact layer (12);(e) forming a first aperture penetrating through said insulating layer (13,
14) and said contact layer (12), thereby separating said contact layer (12) into a pair of spaced-apart contact electrodes (12.1, 12.2); and
thereby exposing a pair of mutually opposed sidewall edges of the contact electrodes (12.1, 12.2) and exposing another portion of the major surface of the body (10) located between said sidewall edges of said contact electrodes (12.1, 12.2);(f) depositing another insulating layer (15) on said intermediate layer (13,
14), on said exposed sidewall edges of the contact electrodes (12.1, 12.2), and on said another portion of the major surface of the body (10);(g) anisotropically etching said another insulating layer (15), whereby material of said another insulating layer (15) remains on said sidewall edges of the contact electrodes (12.1, 12.2), thereby forming mutually opposing sidewall insulating layers (15.1, 15.2) on said sidewall edges and thereby exposing yet another, smaller portion of the major surface of the body (10) therebetween; (h) thermally growing a gate oxide layer (10.3) on the said yet another, smaller portion of the major surface of the body (10); and (i) forming a gate electrode layer (16.3) on said gate oxide layer (10.3), on each of said sidewall insulating layers (15.1, 15.2), and on a selected portion of said intermediate insulating layer (13,
14). - View Dependent Claims (19, 20)
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Specification