High electron mobility transistor semiconductor device and fabrication method thereof
First Claim
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1. A method of forming a semiconductor device on a semiconductor substrate, the method comprising:
- forming a photoresist layer on the semiconductor substrate;
forming a window in the photoresist layer;
forming a conformal layer comprised of a dielectric material on the photoresist layer and in the window;
selectively removing substantially all of the conformal layer from the photoresist layer and a bottom portion of the window to form dielectric sidewalls in the window,depositing a metal film in the window;
isotropically etching the window to remove a portion of the conformal layer from the dielectric sidewalls of the window; and
lifting off the photoresist layer to form a metal gate from the metal film.
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Abstract
In a method of forming a semiconductor device on a semiconductor substrate (100), a photoresist layer (102) is deposited on the semiconductor substrate; a window (106) is formed in the photoresist layer (102) by electron beam lithography; a conformal layer (108) is deposited on the photoresist layer (102) and in the window (106); and substantially all of the conformal layer (108) is selectively removed from the photoresist layer (102) and a bottom portion of the window to form dielectric sidewalls (110) in the window (106).
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Citations
14 Claims
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1. A method of forming a semiconductor device on a semiconductor substrate, the method comprising:
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forming a photoresist layer on the semiconductor substrate; forming a window in the photoresist layer; forming a conformal layer comprised of a dielectric material on the photoresist layer and in the window; selectively removing substantially all of the conformal layer from the photoresist layer and a bottom portion of the window to form dielectric sidewalls in the window, depositing a metal film in the window; isotropically etching the window to remove a portion of the conformal layer from the dielectric sidewalls of the window; and lifting off the photoresist layer to form a metal gate from the metal film.
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2. A method of forming a semiconductor device on a semiconductor substrate, the method comprising:
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forming a photoresist layer on the semiconductor substrate; forming a window in the photoresist layer; forming a conformal layer comprised of a dielectric material on the photoresist layer and in the window; and selectively removing substantially all of the conformal layer from the photoresist layer and a bottom portion of the window to form dielectric sidewalls in the window, wherein the forming of the photoresist layer further includes forming a polymethyl methacrylate (PMMA) layer on the semiconductor substrate and forming a polymethyl methacrylate-methacrylic acid (PMMA-MAA) copolymer layer on the PMMA layer, and further wherein the forming of the conformal layer further includes depositing the dielectric material at a temperature at which the PMMA layer and the PMMA-MAA copolymer layer do not flow.
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3. A method of forming a semiconductor device on a semiconductor substrate, the method comprising:
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forming a photoresist layer on the semiconductor substrate; forming a window in the photoresist layer; forming a conformal layer comprised of a dielectric material on the photoresist layer and in the window; and selectively removing substantially all of the conformal layer from the photoresist layer and a bottom portion of the window to form dielectric sidewalls in the window, wherein the forming of the window in the photoresist layer further includes forming the window by electron beam lithography (EBL). - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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11. A method of forming a metal T-gate on a Group III-V semiconductor substrate, a polymethyl methacrylate (PMMA) layer deposited on the semiconductor substrate, a polymethyl methacrylate-methacrylic acid (PMMA-MAA) copolymer layer deposited on the PMMA layer, and a window formed in the PMMA-MAA copolymer layer and the PMMA layer, the method comprising:
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depositing a dielectric layer on the PMMA-MAA copolymer layer and over the window; selectively removing the dielectric layer to leave dielectric sidewalls in the window; depositing a metal film in the window by evaporation; and lifting off the PMMA layer and the PMMA-MAA copolymer layer to thereby form the metal T-gate from the metal film. - View Dependent Claims (12, 13, 14)
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Specification