Semiconductor device

Claim 1

A semiconductor device of compound semiconduc­tor type comprising: a channel layer (23, 43), and heavily impurity doped source and drain regions (22a, 42a, and 22b, 42b) formed in the surface region of a semiconductor substrate (21, 41), said channel being located between said source and drain regions, and said channel layer, and said source and drain regions being of a first con­ductivity type: and a gate electrode (24, 44), and source and drain electrodes (25a, 45a and 25b, 45b) formed on said semi­conductor substrate (21, 41), said gate electrode cooperating with said channel layer (23, 43) to form a Schottky barrier, and said source and drain electrodes being in ohmic contact with said source and drain regions, characterized in that: a portion of said drain region just under said drain electrode is shallower than a portion of said source region just under said source electrode.

Claim 3

A method of manufacturing a semiconductor device of compound semiconductor type having a channel layer (23, 43), and heavily impurity doped source and drain regions (22a, 42a, and 22b, 42b) formed in the surface region of a semiconductor substrate (21, 41), said channel being located between said source and drain regions, and said channel layer, and said source and drain regions being of a first conductivity type, a gate electrode (24, 44), and source and drain electrodes (25a, 45a and 25b, 45b) formed on said semiconductor substrate (21, 41), said gate electrode cooperating with said channel layer (23, 43) to form a Schottky barrier, and said source and drain electrodes being in ohmic con­tact with said source and drain regions, and a portion of said drain region just under said drain electrode being shallower than a portion of said source region just under said source electrode, said method characterized by comprising the steps of: implanting impurity ions into the different por­tions of said semiconductor substrate separately where source and drain regions are respectively to be formed and is located just under said source and drain electro­des, an ion implanting energy for forming said drain region being smaller than that for forming said source region.

Claim 4

A method of manufacturing a semiconductor device of compound semiconductor type having a channel layer (23, 43), and heavily impurity doped source and drain regions (22a, 42a, and 22b, 42b) formed in the surface region of a semiconductor substrate (21, 41), said channel being located between said source and drain regions, and said channel layer, and said source and drain regions being of a first conductivity type, a gate electrode (24, 44), and source and drain electrodes (25a, 45a and 25b, 45b) formed on said semiconductor substrate (21, 41), said gate electrode cooperating with said channel layer (23, 43) to form a Schottky barrier, and said source and drain electrodes being in ohmic con­tact with said source and drain regions, and a portion of said drain region just under said drain electrode being shallower than a portion of said source region just under said source electrode, said method characterized by comprising the steps of: implanting impurity ions into the different por­tions of said semiconductor substrate separately where source and drain regions are respectively to be formed and is located just under said source and drain electro­des, an ion implanting energy for forming said drain region being smaller than that for forming said source region.

Claim 5

A method of manufacturing a semiconductor device of compound semiconductor type having a channel layer (23, 43), and heavily impurity doped source and drain regions (22a, 42a, and 22b, 42b) formed in the surface region of a semiconductor substrate (21, 41), said channel being located between said source and drain regions, and said channel layer, and said source and drain regions being of a first conductivity type, a gate electrode (24, 44), and source and drain electrodes (25a, 45a and 25b, 45b) formed on said semiconductor substrate (21, 41), said gate electrode cooperating with said channel layer (23, 43) to form a Schottky barrier, and said source and drain electrodes being in ohmic con­tact with said source and drain regions, and a portion of said drain region just under said drain electrode being shallower than a portion of said source region just under said source electrode, said method charac­terized by comprising the steps of: implanting impurity ions into the different por­tions of said semiconductor substrate simultaneously where source and drain regions are respectively to be formed and is located just under said source and drain electrodes, an ion implantation into said drain formed portion being performed through an implanted ion absorp­tion film (52).

Claim 6

A method of manufacturing a semiconductor device of compound semiconductor type having a channel layer (23, 43), and heavily impurity doped source and drain regions (22a, 42a, and 22b, 42b) formed in the surface region of a semiconductor substrate (21, 41), said channel being located between said source and drain regions, and said channel layer, and said source and drain regions being of a first conductivity type, a gate electrode (24, 44), and source and drain electrodes (25a, 45a and 25b, 45b) formed on said semiconductor substrate (21, 41), said gate electrode cooperating with said channel layer (23, 43) to form a Schottky barrier, and said source and drain electrodes being in ohmic con­tact with said source and drain regions, and a portion of said drain region just under said drain electrode being shallower than a portion of said source region just under said source electrode, said method charac­terized by comprising the steps of: implanting impurity ions into the different por­tions of said semiconductor substrate simultaneously where source and drain regions are respectively to be formed and is located just under said source and drain electrodes, an ion implantation into said drain formed portion being performed through an implanted ion absorp­tion film (52).