Vertical Schottky barrier gate field-effect transistor in GaAs/GaAlAs
First Claim
1. A vertical field-effect transistor comprised of epitaxial layers of III-V semiconductor material including a drain layer grown more than one micron thick, a channel layer, and a source layer grown more than one micron thick, with said channel layer grown between said source and drain layers to a controlled submicron thickness for high transconductance of the transistor, and have exposed a cross sectional surface through said channel layer,and further including source and drain contacts for respective one of said source and drain layers, and means for providing a depletion layer of a Schottky barrier gate on the exposed cross sectional surface of said submicron channel layer.
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Abstract
High transconductance vertical FETs are produced in III-V epitaxially grown layers doped n, p and n, with the in-between submicron (0.15 μm) layer serving as the FET channel. The layer on the drain side of the channel may be thicker (3 μm) than on the source side (1.5 μm). The structure is V-grooved to expose a nearly vertical surface that is Si implanted or regrown with graded n-type GaAs/GaAlAs before a gate contact is deposited on the vertical structure. An alternative to employ a heterostructure with GaAlAs layers for the source and drain, and GaAs for the channel layer. Graded GaAs/GaAlAs is then selectively regrown in the channel layer.
127 Citations
10 Claims
- 1. A vertical field-effect transistor comprised of epitaxial layers of III-V semiconductor material including a drain layer grown more than one micron thick, a channel layer, and a source layer grown more than one micron thick, with said channel layer grown between said source and drain layers to a controlled submicron thickness for high transconductance of the transistor, and have exposed a cross sectional surface through said channel layer,and further including source and drain contacts for respective one of said source and drain layers, and means for providing a depletion layer of a Schottky barrier gate on the exposed cross sectional surface of said submicron channel layer.
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7. A high transconductance vertical field-effect transistor comprising epitaxially grown layers of GaAs semiconductor material grown on a substrate of said material doped n+, a first thick layer of about 3 μ
- m in thickness of said material n doped about 1.5×
1017 cm-3, a second thin layer about 0.15 μ
m in thickness of said material p doped from 1 to 2×
1017 cm-3, and a third layer about 1.5 μ
m in thickness of said material n doped about 3×
1017 cm-3, a groove of about 2.5 μ
m depth to expose in a cross sectional surface said second thin layer, source and drain contacts for respective ones of said third layer and substrate, and means for providing a depletion region of a Schottky barrier gate on said exposed cross sectional surface of said second, thin layer. - View Dependent Claims (8, 9)
- m in thickness of said material n doped about 1.5×
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10. A high transconductance vertical field-effect transistor comprising epitaxially grown layers of GaAs and GaAlAs semiconductor materials grown on a substrate of said n+GaAs, a first thick layer about 3 μ
- m in thickness of GaAlAs n doped about 1.5×
1017 cm-3, a second, thin layer about 0.15 μ
m in thickness of GaAs p doped from 1 to 2×
1017 cm-3, and a third layer about 1.5 μ
m in thickness of GaAlAs material in doped about 3×
1017 cm-3 ;
a groove of about 2.5 μ
m depth to expose a cross sectional surface of said second layer, source and drain contacts for respective ones of said third layer and substrate, and means for providing a Schottky barrier gate in the exposed cross sectional surface of said second layer comprised of graded n-type GaAs/GaAlAs selectively regrown over the exposed cross sectional surface of said second layer in said groove and a metal contact deposited over said graded GaAs/GaAlAs selectively regrown.
- m in thickness of GaAlAs n doped about 1.5×
Specification