Mixed-gate metal-oxide-semiconductor varactors
First Claim
1. A mixed gate metal-oxide-semiconductor varactor comprising:
- a semiconductor region;
a gate insulator formed on the semiconductor region; and
at least first and second gate conductors that are formed on the gate insulator and are in contact with each other, wherein the first and second gate conductors form part of a gate structure, wherein the gate structure further comprises a layer of polysilicon formed on the first and second gate conductors that electrically couples the first and second gate conductors, and wherein the first and second gate conductors have different work functions, respectively.
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Accused Products
Abstract
Mixed gate varactors are provided. The mixed gate varactors may include a semiconductor region of a given doping type. A first terminal for the varactor may be formed from a gate structure on the semiconductor region. A second terminal for the varactor may be formed from a heavily doped region in the semiconductor region that has the same doping type as the given doping type. A third terminal for the varactor may be formed from a heavily doped region in the semiconductor region that has a different doping type than the given doping type. The gate structure may include multiple gate conductors on a gate insulator. The gate insulator may be a high-K dielectric. The gate conductors may be metals or other materials that have different work functions. A conductive layer such as a layer of polysilicon may electrically connect the first and second gate conductors.
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Citations
18 Claims
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1. A mixed gate metal-oxide-semiconductor varactor comprising:
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a semiconductor region; a gate insulator formed on the semiconductor region; and at least first and second gate conductors that are formed on the gate insulator and are in contact with each other, wherein the first and second gate conductors form part of a gate structure, wherein the gate structure further comprises a layer of polysilicon formed on the first and second gate conductors that electrically couples the first and second gate conductors, and wherein the first and second gate conductors have different work functions, respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A varactor having a capacitance, comprising:
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a semiconductor having a given doping type; a first terminal that is coupled to the semiconductor by a doped region having the same doping type as the given doping type, wherein the first terminal is operable to receive a first voltage; a second terminal that is coupled to the semiconductor by a doped region having a different doping type than the given doping type, wherein the second terminal is operable to receive a second voltage that is adjustable and that is different than the first voltage, and wherein the second voltage is operable to be controlled for adjusting the capacitance of the varactor; a gate insulating layer on the semiconductor; and a gate structure on the gate insulating layer that has a length and a width that is greater than the length and that forms a third terminal for the varactor, wherein the gate structure comprises a first gate conductor having a first work function and a second gate conductor having second work function that is different than the first work function, wherein the first and second work functions of the first and second gate conductors contribute to the capacitance of the varactor, and wherein the first and second gate conductors are arranged in alternation along the width of the gate structure on a surface of the gate insulating layer. - View Dependent Claims (13)
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14. Variable capacitor circuitry having a capacitance, comprising:
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a semiconductor having a given doping type; a first terminal that is connected to the semiconductor by a doped region having the same doping type as the given doping type, wherein the first terminal is operable to receive a first voltage; a second terminal that is connected to the semiconductor by a doped region having a different doping type than the given doping type, wherein the second terminal is operable to receive a second voltage that is different than the first voltage; a gate insulating layer on the semiconductor; and a gate structure on the gate insulating layer that forms a third terminal for the variable capacitor circuitry, wherein the gate structure comprises a first gate metal on the gate insulating layer, and a second gate metal on the gate insulating layer, wherein the second gate metal has a different work function than the first gate metal, wherein the work function of the first gate metal and the work function of the second gate metal contribute to the capacitance of the variable capacitor circuitry, wherein the gate structure has a length and a width that is greater than the length, and wherein the first gate metal and the second gate metal are arranged in alternation along the width of the gate structure. - View Dependent Claims (15, 16, 17, 18)
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Specification