Abstract: The invention provides gallium nitride material devices, structures and methods of forming the same. The devices include a gallium nitride material formed over a substrate, such as silicon. Exemplary devices include light emitting devices (e.g., LED's, lasers), light detecting devices (such as detectors and sensors), power rectifier diodes and FETs (e.g., HFETs), amongst others.

Abstract: A method of manufacturing a heterojunction device includes forming a first layer of p-type aluminum gallium nitride; forming a second layer of undoped gallium nitride on the first layer; and forming a third layer of aluminum gallium nitride on the second layer, to provide an electron gas between the second and third layers. A heterojunction between the first and second layers injects positive charge into the second layer to compensate and/or neutralize negative charge within the electron gas.

Abstract: A heterojunction device includes a first layer of p-type aluminum gallium nitride; a second layer of undoped gallium nitride on the first layer; a third layer of aluminum gallium nitride on the second layer; and an electron gas between the second and third layers. A heterojunction between the first and second layers injects positive charge into the second layer to compensate and/or neutralize negative charge within the electron gas.

Abstract: A method of compensating resistivity of a near-surface region of a substrate includes epitaxially growing a buffer layer on the substrate, wherein the buffer is grown as having a dopant concentration as dependent on resistivity and conductivity of the substrate, so as to deplete residual or excess charge within the near-surface region of the substrate. The dopant profile of the buffer layer be smoothly graded, or may consist of sub-layers of different dopant concentration, to also provide a highly resistive upper portion of the buffer layer ideal for subsequent device growth. Also, the buffer layer may be doped with carbon, and aluminum may be used to getter the carbon during epitaxial growth.

Abstract: The invention includes providing gallium nitride materials including thermally conductive regions and methods to form such materials. The gallium nitride materials may be used to form semiconductor devices. The thermally conductive regions may include heat spreading layers and heat sinks. Heat spreading layers distribute heat generated during device operation over relatively large areas to prevent excessive localized heating. Heat sinks typically are formed at either the backside or topside of the device and facilitate heat dissipation to the environment. It may be preferable for devices to include a heat spreading layer which is connected to a heat sink at the backside of the device. A variety of semiconductor devices may utilize features of the invention including devices on silicon substrates and devices which generate large amounts of heat such as power transistors.