Non-uniform two-dimensional electron gas profile in III-nitride HEMT devices
AssigneeHRL Laboratories, LLC
InventorsSameh G. Khalil, Karim S. Boutros
Life of this patent
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Abstract
A HEMT device has a substrate; a buffer layer disposed above the substrate; a carrier supplying layer disposed above the buffer layer; a gate element penetrating the carrier supplying layer; and a drain element disposed on the carrier supplying layer. The carrier supplying layer has a non-uniform thickness between the gate element and the drain element, the carrier supplying layer having a relatively greater thickness adjacent the drain element and a relatively thinner thickness adjacent the gate element. A non-uniform two-dimensional electron gas conduction channel is formed in the carrier supplying layer, the two-dimensional electron gas conduction channel having a non-uniform profile between the gate and drain elements.
Claims21
A method of making a HEMT device comprising:
- a. forming a substrate;
- b. disposing a buffer layer above said substrate;
- c. disposing a carrier supplying layer above said buffer layer;
- d. forming a layer of a photoresist on said carrier supplying layer;
- e. forming a plurality of window openings in said layer of a photoresist, said window openings increasing in size beginning at a starting point and ending at an ending point;
- f. etching through the layer of a photoresist at least in a region immediately adjacent said window openings to thereby etch a taper into said carrier supplying layer;
- and
- g. forming a gate element at or immediately adjacent said starting point and forming a drain element at or immediately adjacent said ending point whereby a relatively thin portion of the taper in the carrier supplying layer is disposed next to said gate element, the carrier supplying layer increasing in thickness along said taper to said drain element.
A method of making a HEMT device comprising:
- a. providing a substrate;
- b. disposing a buffer layer above said substrate;
- c. disposing a carrier supplying layer above said buffer layer;
- d. forming a gate element penetrating said carrier supplying layer;
- e. disposing a drain element on said carrier supplying layer;
- f. wherein the carrier supplying layer has a non-uniform thickness in a space separating said gate element and said drain element, the carrier supplying layer having a relatively greater thickness adjacent the drain element and a relatively thinner thickness adjacent the gate element.
A method of making a HEMT device, said method including the step of forming a non-uniform two-dimensional electron gas conduction channel in a carrier supplying layer of the HEMT device between a gate element of the HEMT device and a drain element of the HEMT device, said method also including making said HMET device with a constant electric field distribution between said gate element and said drain element.
A method of making a HEMT device comprising:
- a. providing a substrate;
- b. disposing a buffer layer above said substrate;
- c. disposing a carrier supplying layer above said buffer layer;
- d. forming a gate element;
- e. disposing a drain element on said carrier supplying layer;
- f. forming a two dimensional electron gas (2DEG) between the gate and the drain and wherein the carrier supply layer is configured to adapt the 2DEG such that a variation in electric field strength as a function of a distance between the gate and the drain is substantially constant.
Dependencies are inferred from the claim text.