Yu U Cao, 523100 S Manchester St UNIT 406, Falls Church, VA 22044

2013020, Aug 15, 2013

Jan 18, 2013

13/745046

Kopin Corporation - , US
Yu Cao - Norwood MA, US
Wayne Johnson - Easton MA, US

KOPIN CORPORATION - Taunton MA

H01L 29/15
H01L 21/02
H01L 29/205

257 20, 257 76, 438478

A double heterojunction field effect transistor (DHFET) includes a substrate, a buffer layer consisting of GaN back-barrier buffer layer formed on the substrate, a channel layer consisting of an InGaN ternary alloy in one embodiment, and in another embodiment, InGaN/GaN superlattice (SL) formed on the GaN back-barrier buffer layer opposite to the substrate. A GaN spacer layer is formed on the InGaN or InGaN/GaN superlattice channel layer opposite to the GaN buffer layer and a carrier-supplying layer consisting of an AlInN ternary alloy is formed on the GaN spacer layer opposite to the channel layer. A preferred thickness of the GaN spacer layer is less than about 1.5 nm. The InGaN/GaN SL preferably includes 1 to 5 InGaN—GaN pairs and a preferred thickness of the InGaN layer in the InGaN/GaN SL is equal to or less than about 0.5 nm. A two-dimensional electron gas is formed at the interface between the InGaN or InGaN/GaN SL channel and GaN spacer layers.

2015000, Jan 1, 2015

Jun 27, 2013

13/929161

- Taunton MA, US
Yu Cao - Norwood MA, US
Wayne Johnson - Easton MA, US

IQE KC, LLC - Taunton MA

H01L 29/778
H01L 29/66

257190, 438172

An iron-doped high-electron-mobility transistor (HEMT) structure includes a substrate, a nucleation layer over the substrate, and a buffer layer over the nucleation layer. The gallium-nitride buffer layer includes a iron-doping-stop layer having a concentration of iron that drops from a juncture with an iron-doped component of the buffer layer over a thickness that is relatively small compared to that of the iron-doped component. The iron-doping-stop layer is formed at lower temperature compared to the temperature at which the iron-doped component is formed. The iron-doped HEMT structure also includes a channel layer over the buffer layer. A carrier-supplying barrier layer is formed over the channel layer.

2014016, Jun 19, 2014

Aug 22, 2013

13/973377

- Taunton MA, US
Yu Cao - Norwood MA, US
Wayne Johnson - Easton MA, US

IQE, KC, LLC - Taunton MA

H01L 29/778
H01L 29/205
H01L 21/02
H01L 29/66

257 76, 438478

An epitaxial structure on a substrate includes a gallium nitride buffer layer over the substrate and a graded channel layer over the gallium nitride layer. The graded channel layer consists essentially of InGaN wherein the value of x gets smaller from a first surface of the channel layer proximate to a buffer layer to a second surface remote from the buffer layer.