Hrl Laboratories, LLC

Shawn D Burnham

Miroslav Micovic

Andrea Corrion

Keisuke Shinohara

Paul B Hashimoto

Hooman Kazemi

Peter J Willadsen

Rongming Chu

Karim S Boutros

Alexandros Margomenos

Tahir Hussain

David F Brown

Wah S Wong

Dean C Regan

Mary Y Chen

Zijian “Ray” Li

Samuel Kim

Keisuke Shinihara

A method of making a stepped field gate for an FET including forming a first passivation layer on a barrier layer, defining a first field plate by using electron beam (EB) lithography and by depositing a first negative EB resist, forming a second passivation layer over first negative EB resist and the first passivation layer, planarizing the first negative EB resist and the second passivation layer, defining a second field plate by using EB lithography and by depositing a second negative EB resist connected to the first negative EB resist, forming a third passivation layer over second negative EB resist and the second passivation layer, planarizing the second negative EB resist and the third passivation layer, removing the first and second negative EB resist, and forming a stepped field gate by using lithography and plating in a void left by the removed first and second negative EB resist.

Stepped field plate wide bandgap field-effect transistor and method

The interface resistance between the source/drain and gate of an HFET may be significantly reduced by engineering the bandgap of the 2DEG outside a gate region such that the charge density is substantially increased. The resistance may be further reduced by using an n+GaN Cap layer over the channel layer and barrier layer such that a horizontal surface of the barrier layer beyond the gate region is covered by the n+GaN Cap layer. This technique is applicable to depletion and enhancement mode HFETs.

Apparatus and method for reducing the interface resistance in GaN Heterojunction FETs

A method of fabricating a normally 'off' GaN heterostructure field effect transistor having a source and a drain including depositing a passivation layer patterned to cover a channel region between a source and a drain, forming a first opening in the passivation layer, the first opening for defining a gate area in the channel region and the first opening having a first length dimension along a direction of current flow between the source and the drain, and implanting ions in an implant area within the gate area, wherein the implant area has a second length dimension along the direction of current flow shorter than the first length dimension.

Enhancement mode normally-off gallium nitride heterostructure field effect transistor

A method of fabricating a GaN HEMT includes growing a first epitaxial layer on a substrate, growing a second epitaxial layer on the first epitaxial layer, growing a third epitaxial layer on the second epitaxial layer, depositing a first dielectric film on the third epitaxial layer, using dielectric films to form a first sidewall dielectric spacer, forming a sidewall gate adjacent the first sidewall dielectric spacer. The sidewall gate may be made to be less than 50 nm in length.

Self-aligned sidewall gate GaN HEMT

The present invention relates to fabrication of enhancement mode and depletion mode High Electron Mobility Field Effect Transistors on the same die separated by as little as 10 nm. The fabrication method uses selective decomposition and selective regrowth of the Barrier layer and the Cap layer to engineer the bandgap of a region on a die to form an enhancement mode region. In these regions zero or more devices may be fabricated.

Enhancement and depletion mode GaN HMETs on the same substrate

Apparatus and method for reducing the interface resistance in GaN heterojunction FETs

A field effect transistor (FET) includes source and drain electrodes, a channel layer, a barrier layer over the channel layer, a passivation layer covering the barrier layer for passivating the barrier layer, a gate electrode extending through the barrier layer and the passivation layer, and a gate dielectric surrounding a portion of the gate electrode that extends through the barrier layer and the passivation layer, wherein the passivation layer is a first material and the gate dielectric is a second material, and the first material is different than the second material.

AlGaN/GaN hybrid MOS-HFET

A field effect transistor (FET) having a source contact to a channel layer, a drain contact to the channel layer, and a gate contact on a barrier layer over the channel layer, the FET including a dielectric layer on the barrier layer between the source contact and the drain contact and over the gate contact, and a field plate on the dielectric layer, the field plate connected to the source contact and extending over a space between the gate contact and the drain contact and the field plate comprising a sloped sidewall in the space between the gate contact and the drain contact.

High current high voltage GaN field effect transistors and method of fabricating same

Self aligned sidewall gate GaN HEMT

A two stage plasma etching technique is described that allows the fabrication of an enhancement mode GaN HFET/HEMT. A gate recess area is formed in the Aluminum Gallium Nitride barrier layer of an GaN HFET/HEMT. The gate recess is formed by a two stage etching process. The first stage of the technique uses oxygen to oxidize the surface of the Aluminum Gallium Nitride barrier layer below the gate. Then the second stage uses Boron tricloride to remove the oxidized layer. The result is a self limiting etch process that uniformly thins the Aluminum Gallium Nitride layer below the HFET's gate region such that the two dimensional electron gas is not formed below the gate, thus creating an enhancement mode HFET.

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Oxnard, CA, United States of America

Shawn D Burnham