Abstract: Bulk acoustic wave (BAW) resonators, and electrical filters that incorporate the BAW resonators, are described. Generally, the BAW resonators comprise a substrate comprising an acoustic reflector; a first electrode disposed over the acoustic reflector; a piezoelectric layer disposed over the first electrode, the piezoelectric layer comprising scandium-doped aluminum nitride (ASN); a diffusion barrier layer disposed over the piezoelectric layer; and a second electrode disposed over the diffusion barrier layer. The diffusion barrier layer configured to prevent diffusion of material of the first electrode into the piezoelectric layer.

Abstract: Bulk acoustic wave (BAW) resonators, and electrical filters that incorporate the BAW resonators, are described. Generally, the BAW resonators comprise a substrate comprising an acoustic reflector; a first electrode disposed over the acoustic reflector; a piezoelectric layer disposed over the first electrode, the piezoelectric layer comprising scandium-doped aluminum nitride (ASN); a diffusion barrier layer disposed over the piezoelectric layer; and a second electrode disposed over the diffusion barrier layer. The diffusion barrier layer configured to prevent diffusion of material of the first electrode into the piezoelectric layer.

Abstract: A method is provided for calibrating a device under calibration (DUC) for optimizing performance of the DUC.

Abstract: A pseudomorphic high electron mobility transistor (pHEMT) comprises: a substrate comprising a Group III-V semiconductor material; buffer layer disposed over the substrate; and a channel layer disposed over the buffer layer. The buffer layer comprises microprecipitates of a Group V semiconductor element. A method of fabricating a pHEMT is also described.

Abstract: A pseudomorphic high electron mobility transistor (PHEMT) comprises a substrate comprising a Group III-V semiconductor material, a buffer layer disposed over the substrate, wherein the buffer layer comprises microprecipitates of a Group V semiconductor element and is doped with an N-type dopant, and a channel layer disposed over the buffer layer.

Abstract: A pseudomorphic high electron mobility transistor (PHEMT) comprises a substrate comprising a Group III-V semiconductor material, a buffer layer disposed over the substrate, wherein the buffer layer comprises microprecipitates of a Group V semiconductor element and is doped with an N-type dopant, and a channel layer disposed over the buffer layer.

Abstract: A pseudomorphic high electron mobility transistor (pHEMT) comprises: a substrate comprising a Group III-V semiconductor material; buffer layer disposed over the substrate; and a channel layer disposed over the buffer layer. The buffer layer comprises microprecipitates of a Group V semiconductor element. A method of fabricating a pHEMT is also described.

Abstract: A heterojunction for a semiconductor device. The heterojunction has a first region formed from a first semiconductor material having a first conductivity type, a second region formed from a second semiconductor material having a second conductivity type, and an intermediate layer between the first region and the second region. The band line-up of the first region, the intermediate layer, and the second region has no bound states in its conduction band and no bound states in its valence band. The intermediate layer has a thickness small enough to allow electrons to tunnel from the first region to the second region with negligible attenuation. The semiconductor device may be a heterojunction bipolar transistor. The conduction band of the intermediate layer has a higher energy level than the conduction bands of the first and second regions.

Abstract: A heterojunction for a semiconductor device. The heterojunction has a first region formed from a first semiconductor material having a first conductivity type, a second region formed from a second semiconductor material having a second conductivity type, and an intermediate layer between the first region and the second region. The band line-up of the first region, the intermediate layer, and the second region has no bound states in its conduction band and no bound states in its valence band. The intermediate layer has a thickness small enough to allow electrons to tunnel from the first region to the second region with negligible attenuation. The semiconductor device may be a heterojunction bipolar transistor. The conduction band of the intermediate layer has a higher energy level than the conduction bands of the first and second regions.