Method of manufacturing metal-semiconductor contacts exhibiting high injected current density
AssigneeThomson-CSF
InventorsPaul C. Moutou, Jacques Montel
Life of this patent
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Abstract
A method for virtually eliminating contact resistances in particular at very high frequency, for instance in the case of source and drain contacts of a field effect transistor. The method consists in creating a matrix of depressions or "dishes", for example 1 to 6 microns in diameter, separated by intervals of some few microns. In a first step, windows are opened in an insulating layer by an etching operation. In a second step, by ion machining, angular profiles are carved in the bottom of the dishes for promoting tunnel effect. In a last step a metal layer is deposited and enshrouds the matrix.
Claims10
A method of manufacturing "metal semiconductor" contacts destined to be employed together as a single contact, consisting of:
- (I) depositing an insulating layer onto the surface of a semiconductor;
- (II) forming in said insulating layer and in a superficial portion of said semiconductor a matrix of microscopic depressions having a major dimension d, said depressions separated by an interval e, wherein
- 0.1 micron.ltoreq.d.ltoreq.10 microns
- 1.5 micron.ltoreq.e.ltoreq.30 microns;
- (III) depositing a layer of conductive material in said depressions until a single conductive layer covering the matrix of depressions is formed;
- said matrix of depressions and said insulating layer being completely enshrouded by a substantially planar layer of said conductive material and the thickness thereof being substantially uniform over the entire surface area of said insulating layer and the matrix of depressions contained therein to thereby increase the injected current density and concurrently substantially eliminate contact resistances of said contacts.
A method as claimed in claim 8, wherein said metal, by doping of the semiconductor material, forms a rectifying junction.
A method of manufacturing "metal semiconductor" contacts destined to be employed together as a single contact, consisting of:
- (I) depositing an insulating layer of silica onto the surface of a semiconductor;
- (II) forming windows in said insulating silica layer by an etching operation and excavating said windows by an ion machining step in a superficial portion of said semiconductor to form a matrix of microscopic depressions having a major dimension d, said depressions separated by an interval e, wherein
- 0.1 micron.ltoreq.d.ltoreq.10 microns
- 1. 5 micron.ltoreq.e.ltoreq.30 microns;
- (III) depositing a layer of conductive metal material in said depressions until a single conductive layer covering the matrix of depressions is formed;
- heat treating following the deposition;
- said matrix of depressions and said insulating layer being completely enshrouded by a substantially planar layer of said conductive material and the thickness thereof being substantially uniform over the entire surface area of said insulating layer and the matrix of depressions contained therein to thereby increase the injected current density and concurrently substantially eliminate contact resistances of said contacts.
Dependencies are inferred from the claim text.