Semiconductor device manufacturing: process – Making field effect device having pair of active regions... – Having schottky gate
Reexamination Certificate
2005-03-15
2005-03-15
Kang, Donghee (Department: 2811)
Semiconductor device manufacturing: process
Making field effect device having pair of active regions...
Having schottky gate
C438S172000, C438S175000, C438S182000, C438S285000, C438S590000, C257S183000, C257S192000, C257S194000, C257S195000
Reexamination Certificate
active
06867078
ABSTRACT:
A microwave field effect transistor (10) has a high conductivity gate (44) overlying a double heterojunction structure (14, 18, 22) that has an undoped channel layer (18). The heterojunction structure overlies a substrate (12). A recess layer that is a not intentionally doped (NID) layer (24) overlies the heterojunction structure and is formed with a predetermined thickness that minimizes impact ionization effects at an interface of a drain contact of source/drain ohmic contacts (30) and permits significantly higher voltage operation than previous step gate transistors. Another recess layer (26) is used to define a gate dimension. A Schottky gate opening (42) is formed within a step gate opening (40) to create a step gate structure. A channel layer (18) material of InxGa1−xAs is used to provide a region of electron confinement with improved transport characteristics that result in higher frequency of operation, higher power density and improved power-added efficiency.
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Green Bruce M.
Hartin Olin L.
Klingbeil Lawrence S.
Lan Ellen Y.
Li Hsin-Hua P.
Bolconi-Lamica Michael
Freescale Semiconductor Inc.
Kang Donghee
King Robert L.
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