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US 8,525,226 B2Granted
Field effect transistor with frequency dependent gate-channel capacitance
AssigneeSensor Electronic Technology, Inc.
InventorsGrigory Simin, Michael Shur, Remigijus Gaska
Life of this patent
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Abstract
A field effect transistor having a channel, a gate, and a structure for decreasing a gate-to-channel capacitance of the transistor as an operating frequency of the transistor increases. The structure can comprise, for example, a barrier disposed between the gate and the channel, which has a dielectric permittivity and/or a conductivity that varies with an operating frequency of the transistor. In an embodiment, the barrier comprises a layer of conducting material, such as conducting polymer, conducting semiconductor, conducting semi-metal, amorphous silicon, polycrystalline silicon, and/or the like.
Claims19
A field effect transistor comprising:
- a channel;
- a gate to the channel;
- and
- a barrier located between the gate and the channel, wherein the barrier is configured to decrease a gate-to-channel capacitance of the transistor as an operating frequency of the transistor increases such that a corresponding threshold voltage of the transistor increases as the operating frequency of the transistor increases, and wherein the barrier includes:
- a first barrier layer formed of a nitride material having a first resistance and a first capacitance, wherein the first barrier layer is located directly on the channel;
- and
- a second barrier layer comprising a layer of non-dielectric conducting material, the second barrier layer having a second resistance and a second capacitance, wherein the second barrier layer is located on the first barrier layer and the gate is located directly on the second barrier layer,
- wherein, at an operating frequency above a minimal operating frequency, the first resistance is at least ten times larger than the second resistance,
- wherein, at an operating frequency above the minimal operating frequency, the first capacitance is at least two times larger than the second capacitance, and
- wherein a product of the second resistance and the second capacitance is larger than an inverse of an operating frequency of the transistor above the minimal operating frequency.
7 more elements
A field effect transistor comprising:
- a channel;
- a gate to the channel;
- and
- means for decreasing a gate-to-channel capacitance of the transistor as an operating frequency of the transistor increases such that a corresponding threshold voltage of the transistor increases as the operating frequency of the transistor increases, and wherein the threshold voltage at an operating frequency greater than a transition range of frequencies is at least two times higher than a threshold voltage of the transistor at an operating frequency below the transition range of frequencies, wherein the means for decreasing includes:
- a nitride-based barrier layer located directly on the channel;
- and
- a layer of conducting material located directly on the barrier layer, wherein the gate is located directly on the layer of conducting material.
4 more elements
A field effect transistor comprising:
- a channel;
- a gate to the channel;
- and
- a barrier located between the gate and the channel, wherein the barrier comprises:
- a layer of non-dielectric conducting material selected from the group consisting of:
- conducting polymer, conducting semiconductor, conducting semi-metal, amorphous silicon, and polycrystalline silicon, wherein the layer of conducting material has a first resistance and a first capacitance;
- and
- a barrier layer formed of a nitride material disposed between the channel and the layer of conducting material, wherein the barrier layer has a second resistance and a second capacitance,
- wherein the barrier layer is located directly on the channel, the layer of non-dielectric conducting material is located directly on the barrier layer, and the gate is located directly on the layer of non-dielectric conducting material,
- wherein, at an operating frequency above a minimal operating frequency, the first resistance is at least ten times larger than the second resistance,
- wherein, at an operating frequency above a minimal operating frequency, the first capacitance is at least two times larger than the second capacitance, and
- wherein a product of the second resistance and the second capacitance is larger than an inverse of an operating frequency of the transistor above the minimal operating frequency.
9 more elements
Dependencies are inferred from the claim text.