Abstract: A semiconductor structure includes a substrate and a semiconductor buffer structure overlying the substrate. The semiconductor buffer structure includes a semiconductor body of a gallium nitride material, and a stack of strain compensation layers. The stack of strain compensation layers includes a layer of a first semiconductor material with an in-plane lattice constant that is smaller than a lattice constant of the semiconductor body, and a layer of a second semiconductor material with an in-plane lattice constant that is greater than the lattice constant of the semiconductor body.

Abstract: A semiconductor structure includes a substrate and a semiconductor buffer structure overlying the substrate. The semiconductor buffer structure includes a semiconductor body of a gallium nitride material, and a stack of strain compensation layers. The stack of strain compensation layers includes a layer of a first semiconductor material with an in-plane lattice constant that is smaller than a lattice constant of the semiconductor body, and a layer of a second semiconductor material with an in-plane lattice constant that is greater than the lattice constant of the semiconductor body.

Abstract: Structures and fabrication processes are described for group III-nitride enhancement mode field effect devices in which a two-dimensional electron gas is present at or near the interface between a pair of active layers that include a group III-nitride barrier layer and a group III-nitride semiconductor layer. The barrier layer has a band gap wider than the band gap of the adjacent underlying semiconductor layer. The two-dimensional electron gas is induced by providing one or more layers disposed over the barrier layer. A gate electrode is in direct contact with the barrier layer. Ohmic contacts for source and drain electrodes are in direct contact either with the barrier layer or with a semiconductor nitride layer disposed over the barrier layer.

Abstract: Structures and fabrication processes are described for group III-nitride enhancement mode field effect devices in which a two-dimensional electron gas is present at or near the interface between a pair of active layers that include a group III-nitride barrier layer and a group III-nitride semiconductor layer. The barrier layer has a band gap wider than the band gap of the adjacent underlying semiconductor layer. The two-dimensional electron gas is induced by providing one or more layers disposed over the barrier layer. A gate electrode is in direct contact with the barrier layer. Ohmic contacts for source and drain electrodes are in direct contact either with the barrier layer or with a semiconductor nitride layer disposed over the barrier layer.

Abstract: A method of fabricating an epitaxial compound semiconductor III-V wafer suitable for the subsequent fabrication of at least two different types of integrated active devices (such as an HBT and a FET) on such wafer by providing a substrate; growing a first epitaxial structure on the substrate; and growing a second epitaxial structure on the first epitaxial structure.