Heterojunction field effect transistor having gate threshold voltage capability
First Claim
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1. A monocrystalline semiconductor heterojunction field effect transistor having a selectively controlled gate threshold voltage comprising:
- a substrate having doped source and drain regions with a doping level of ≧
1018 atoms/cm3, and a semiconductor channel region located between said source and drain regions;
a gate insulator comprising a first undoped semiconductor material region adjacent said channel region and having a wide band gap;
a threshold voltage controlling layer comprising a second region of semiconductor material with a narrower band gap than said first undoped semiconductor region and being different from said first undoped semiconductor material region and being separated from said channel region by said gate insulator and being doped with about 1017 to about 1019 atoms/cm3 and being a gate region;
a third region of semiconductor material being doped with at least 2×
1018 atoms/cm3 and being adjacent said threshold voltage controlling voltage layer and having a narrower band gap than the band gap of said threshold voltage controlling layer and being a gate region; and
ohmic contact means to said third region.
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Abstract
A field effect transistor comprising a semiconductor channel region; an undoped semiconductor material region adjacent the channel region; a second semiconductor material region separated from the channel region; and a region of semiconductor material adjacent the second region and having a narrower band gap than the band gap of the region adjacent the channel region; and ohmic contact means to the region having the narrower band gap.
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Citations
19 Claims
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1. A monocrystalline semiconductor heterojunction field effect transistor having a selectively controlled gate threshold voltage comprising:
a substrate having doped source and drain regions with a doping level of ≧
1018 atoms/cm3, and a semiconductor channel region located between said source and drain regions;
a gate insulator comprising a first undoped semiconductor material region adjacent said channel region and having a wide band gap;
a threshold voltage controlling layer comprising a second region of semiconductor material with a narrower band gap than said first undoped semiconductor region and being different from said first undoped semiconductor material region and being separated from said channel region by said gate insulator and being doped with about 1017 to about 1019 atoms/cm3 and being a gate region;
a third region of semiconductor material being doped with at least 2×
1018 atoms/cm3 and being adjacent said threshold voltage controlling voltage layer and having a narrower band gap than the band gap of said threshold voltage controlling layer and being a gate region; and
ohmic contact means to said third region.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A monocrystalline semiconductor heterojunction field effect transistor having a selectively controlled gate threshold voltage comprising:
a substrate having doped source and drain regions with a doping level of ≧
1018 atoms/cm3, and a semiconductor channel region located between said source and drain regions;
a gate insulator comprising a first undoped semiconductor material region adjacent said channel region and having a wide band gap;
a threshold voltage controlling layer comprising a second undoped region of semiconductor material with a narrower band gap than said first undoped semiconductor region and being different from said first undoped semiconductor material region and being separated from said channel region by said gate insulator and being an insulator;
a third region of semiconductor material being doped with at least 2×
1018 atoms/cm3 and being adjacent said threshold voltage controlling layer and having a narrower band gap than the band gap of said threshold voltage controlling layer and being a gate region; and
ohmic contact means to said third region.- View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19)
Specification