Semiconductor devices with Schottky barriers
Circuits, systems, devices, and methods related to transistors with Schottky barriers are discussed herein. For example, a method of fabricating a transistor can include forming a p-well or an n-well in a substrate and forming a gate for the transistor. The method can also include doping a region within the p-well or n-well with a concentration below a threshold and forming a conductor layer on the doped region.
1 . A method of fabricating a transistor, the method comprising:
forming a p-well or an n-well on an insulator layer;
forming a gate for the transistor, the transistor comprising a Silicon-on-Insulator (SOI) device;
doping a first region within the p-well or the n-well with a concentration that is below a threshold to form a source for the transistor;
doping a second region within the p-well or the n-well with the concentration to form a drain for the transistor, at least a portion of the gate being disposed directly in-line with and between the first region and the second region; and
forming a first contact on the first region and a second contact on the second region.
2 . The method of claim 1 wherein the first contact on the first region forms a non-ohmic contact.
3 . The method of claim 1 wherein at least a portion of the p-well or the n-well is disposed between the source and the drain of the transistor.
4 . The method of claim 1 wherein the concentration is less than a doping concentration associated with an ohmic contact.
5 . The method of claim 1 wherein the concentration is less than, by a least a threshold amount, a doping concentration of an ohmic contact.
6 . The method of claim 1 further comprising forming the insulator layer on a substrate to form the transistor as the SOI device.
7 . The method of claim 1 wherein the first region and first contact form the source for the transistor and the second region and second contact form the drain for the transistor.
8 . The method of claim 1 wherein the first region extends beyond the p-well or the n-well and forms an exposed surface.
9 . A radio-frequency switch comprising:
an input node;
an output node; and
a transistor connected between the input node and the output node, the transistor being configured to control passage of a radio-frequency signal from the input node to the output node, the transistor including a p-well or an n-well, a first region within the p-well or the n-well, a second region within the p-well or the n-well, a first contact disposed on the first region, and a second contact disposed on the second region, the first region and the second region being doped with a concentration below a threshold, the transistor is implemented as a Silicon-on-Insulator (SOI) device, the first region extending beyond a surface of the p-well or the n-well.
10 . The radio-frequency switch of claim 9 wherein the first region and first contact form a Schottky barrier.
11 . The radio-frequency switch of claim 10 wherein the Schottky barrier is configured to compensate for third order distortion.
12 . The radio-frequency switch of claim 9 wherein the first region forms at least a portion of a source for the transistor and the second region forms at least a portion of a drain for the transistor.
13 . The radio-frequency switch of claim 9 wherein the first and second contacts are each a metal contact.
14 . The radio-frequency switch of claim 9 wherein the first contact disposed on the first region forms a non-ohmic contact.
15 . The radio-frequency switch of claim 9 wherein at least a portion of the p-well or the n-well is disposed between the first region and the second region.
16 . The radio-frequency switch of claim 9 wherein the first region is an exposed surface.
17 . A transistor comprising:
a substrate;
an insulator layer formed on the substrate;
a p-well or an n-well formed on the insulator layer;
a first region in the p-well or the n-well that is doped with a concentration below a threshold, the first region forming an exposed surface along the p-well or n-well;
a second region in the p-well or the n-well that is doped with the concentration;
a first contact disposed on the first region; and
a second contact disposed on the second region.
18 . The transistor of claim 17 wherein the first region forms at least a portion of a source for the transistor and the second region forms at least a portion of a drain for the transistor.
19 . The transistor of claim 17 wherein the first region and first contact form a Schottky barrier.
20 . A radio-frequency device comprising:
a transceiver configured to generate a radio-frequency signal;
a power amplifier coupled to the transceiver and configured to generate an amplified radio-frequency signal; and
a radio-frequency switch including the transistor of claim 17 , the radio-frequency switch being coupled to the power amplifier and being configured to selectively route the amplified radio-frequency signal.