Heterojunction Schottky gate MESFET with lower channel ridge barrier
First Claim
1. A semiconductor switching device including in combination:
- a doped semiconductor substrate of the first conductivity type and of a first material with one surface thereof being approximately flat but with a ridge structure rising from a portion of said flat surface;
a semiconductor layer of a second material disposed over the flat surface and ridge structure of said substrate to form an epitaxial heterojunction interface therewith, heavily doped source and drain regions of the first conductivity type being formed down into said semiconductor layer on opposite sides of said ridge structure;
source and drain ohmic contacts being disposed on said semiconductor layer above said source and drain regions;
a gate material being disposed on said semiconductor layer above said substrate ridge structure to form a barrier with said semiconductor layer.
1 Assignment
0 Petitions
Accused Products
Abstract
An FET with an extremely short channel formed by the apex of a substrate ridge structure protruding upward through the channel layer toward a Schottky-barrier gate contact. The device is formed by etching a modulation-doped substrate to form an upwardly protruding ridge with the apex modulation-doped. A semiconductor layer is then disposed over the substrate surface with the protruding ridge to obtain an epitaxial interface therebetween. Source and drain regions are doped into the semiconductor layer on opposite sides of the ridge structure. Finally, ohmic contacts are formed on the semiconductor layer over the source and drain regions and a Schottky-barrier metalization is deposited on the semiconductor layer above the ridge structure. This device has a very short channel, a low transit time, a low gate capacitance, and an enhanced transconductance.
106 Citations
11 Claims
-
1. A semiconductor switching device including in combination:
-
a doped semiconductor substrate of the first conductivity type and of a first material with one surface thereof being approximately flat but with a ridge structure rising from a portion of said flat surface; a semiconductor layer of a second material disposed over the flat surface and ridge structure of said substrate to form an epitaxial heterojunction interface therewith, heavily doped source and drain regions of the first conductivity type being formed down into said semiconductor layer on opposite sides of said ridge structure; source and drain ohmic contacts being disposed on said semiconductor layer above said source and drain regions; a gate material being disposed on said semiconductor layer above said substrate ridge structure to form a barrier with said semiconductor layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
-
-
9. A field-effect transistor including in combination:
-
a semiconductor substrate of the first conductivity type and of a first material with one surface thereof being approximately flat but with a ridge structure rising from a portion of said flat surface, said ridge structure being modulation-doped along an edge portion thereof; a semiconductdor layer of a second material disposed over the flat surface and ridge structure of said substrate to form an epitaxial heterojunction interface therewith, heavily doped source and drain regions of the first conductivity type being formed in said semiconductor layer on opposite sides of said ridge structure essentially down to said substrate. source and drain ohmic contacts being disposed on said semiconductor layer above said source and drain regions; and a Schottky-barrier material being disposed on said semiconductor layer above said substrate ridge structure to form a gate contact. - View Dependent Claims (10, 11)
-
Specification