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US 12,402,348 B2Granted
Field effect transistor with selective channel layer doping
AssigneeWolfspeed, Inc.
InventorsJia Guo, Saptharishi Sriram, Scott Sheppard
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Abstract
A transistor device according to some embodiments includes a channel layer, a barrier layer on the channel layer, and source and drain contacts on the barrier layer, and a gate contact on the barrier layer between the source and drain contacts. The channel layer includes a sub-layer having an increased doping concentration level relative to a remaining portion of the channel layer. The presence of the sub-layer may reduce drain lag without substantially increasing gate lag.
Claims21
A transistor device, comprising:
- a substrate;
- a channel layer formed on the substrate;
- a barrier layer on the channel layer;
- and
- a source contact and a drain contact on the barrier layer, and a gate contact that terminates on a surface of the barrier layer between the source and drain contacts;
- wherein the channel layer comprises a first sub-layer, a second sub-layer on the first sub-layer, and a third sub-layer on the second sub-layer, wherein the first sub-layer is between the second sub-layer and the substrate and the second sub-layer is between the first sub-layer and the third sub-layer;
- wherein the first sub-layer is doped with n-type dopants at a first doping concentration, the second sub-layer is doped with n-type dopants at a second doping concentration, and the third sub-layer is doped with n-type dopants at a third doping concentration, wherein the second doping concentration is greater than the first doping concentration.
4 more elements
A transistor device, comprising:
- a substrate;
- a channel layer on the substrate;
- a barrier layer on the channel layer;
- and
- source and drain contacts on the barrier layer, and a gate contact that terminates on a surface of the barrier layer between the source and drain contacts;
- wherein the channel layer comprises a first sub-layer having a first doping concentration level, a second sub-layer having a second doping concentration level on the first sub-layer, and a third sub-layer having a third doping concentration level on the second sub-layer opposite the first sub-layer, wherein the third sub-layer is adjacent the barrier layer, and wherein the first sub-layer is between the second sub-layer and the substrate, wherein each of the first sub-layer, the second sub-layer, and the third sub-layer is doped with an n-type dopant;
- wherein the second doping concentration level is higher than the first doping concentration level and the third doping concentration level,
- wherein the second doping concentration level is greater than 2E16 cm−3, and
- wherein the first and third doping concentration levels are each less than about 2E16 cm−3.
6 more elements
Dependencies are inferred from the claim text.