Abstract: 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.

Abstract: 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.