Monde Wireless Inc.

University of California

Brian Romanczyk

Matthew Guidry

Umesh Kumar Mishra

Stacia Keller

Xun Zheng

Elaheh Ahmadi

Haoran Li

Steven Wienecke

In order to reduce costs as well as to effectively dissipate heat in certain RF circuits, a semiconductor device of the circuit can include one or more active devices such as transistors, diodes, and/or varactors formed of a first semiconductor material system integrated onto (e.g., bonded to) a base substrate formed of a second semiconductor material system that includes other circuit components. The first semiconductor material system can, for example, be the III-V or III-N semiconductor system, and the second semiconductor material system can, for example be silicon.

Semiconductor device for RF integrated circuit

A wireless front-end can include a plurality of circuits, including a power amplifier (PA), a low noise amplifier (LNA), and an RF switch. In order to decrease the size and improve the performance of the front-end, the various circuits of the front end can include N-polar III-N transistors that are all formed from the same epitaxial material structure and monolithically integrated onto a single chip. Due to the different performance requirements of the various transistors in the different circuits, parameters such as gate length, gate-to-channel separation, and surface-to-channel separation in the access regions of the devices can be varied to meet the desired performance requirements.

Devices for integrated front-end circuits

An N-polar III-N high-electron mobility transistor device can include a III-N channel layer over an N-face of a III-N backbarrier, wherein a compositional difference between the channel layer and the backbarrier causes a 2DEG channel to be induced in the III-N channel layer adjacent to the interface between the III-N channel layer and the backbarrier. The device can further include a p-type III-N layer over the III-N channel layer and a thick III-N cap layer over the p-type III-N layer. The III-N cap layer can cause an increase in the charge density of the 2DEG channel directly below the cap layer, and the p-type III-N layer can serve to prevent a parasitic 2DEG from forming in the III-N cap layer.

N-polar III-nitride device structures with a p-type layer

Described herein are III-N (e.g. GaN) devices having a stepped cap layer over the channel of the device, for which the III-N material is orientated in an N-polar orientation.

III-N transistor structures with stepped cap layers

A novel design for a nitrogen polar high-electron-mobility transistor (HEMT) structure comprising a GaN/InGaN composite channel. As A novel design for a nitrogen polar high-electron-mobility transistor (HEMT) structure comprising a GaN/InGaN composite channel. As illustrated herein, a thin InGaN layer introduced in the channel increases the carrier density, reduces the electric field in the channel, and increases the carrier mobility. The dependence of p on InGaN thickness (InGaN) and indium composition (In) was investigated for different channel thicknesses. With optimizedInGaN andIn, significant improvements in electron mobility were observed. For a 6 nm channel HEMT, the electron mobility increased from 606 to 1141 cm/(V&#xb7;s) when the 6 nm thick pure GaN channel was replaced by the 4 nm GaN/2 nm InGaN composite channel.

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Santa Barbara, CA, United States of America

Brian Romanczyk