Abstract: A fully depleted “diode passivation active passivation architecture” (DPAPA) produces a photodiode structure which includes a substrate, a highly-doped buffer layer of a first carrier doping type above the substrate, a low-doped or undoped semiconductor active layer of the first carrier doping type above the buffer layer, a low-doped or undoped passivation layer above the active layer, the passivation layer having a wider band gap than the active layer; and a junction layer of a carrier doping type opposite the first carrier doping type above the passivation layer such that a pn junction is formed between the junction layer and the passivation and active layers, the junction creating a depletion region which expands completely through the passivation and active layers in response to a reverse bias voltage. The fully depleted structure substantially eliminates Auger recombination, reduces dark currents and enables cryogenic level performance at high temperatures.

Abstract: The present invention provides a heterojunction photodiode which includes a pn or Schottky-barrier junction formed in a first material region having a bandgap energy Eg1. When reverse-biased, the junction creates a depletion region which expands towards a second material region having a bandgap energy Eg2 which is less than Eg1. This facilitates signal photocurrent generated in the second region to flow efficiently through the junction in the first region while minimizing the process-related dark currents and associated noise due to near junction defects and imperfect surfaces which typically reduce photodiode device performance. The heterojunction photodiode can be included in an imaging system which includes an array of junctions to form an imager.

Abstract: A Schottky rectifier has multiple stages with substantially identical or very similar structures. Each stage includes a nitride-based semiconductor layer, a Schottky contact formed on one surface of the semiconductor layer, and an ohmic contact formed on an opposite surface of the semiconductor layer. The Schottky layer is formed from a metallic material with a high metal work function, and the ohmic contact is formed from a metallic material with a low metal work function. At least one of the stages is a middle stage located between two adjacent stages, such that the Schottky contact of the middle stage and the ohmic contact of one of the adjacent stages are joined together, and such that the ohmic contact of the middle stage and the Schottky contact of another one of the adjacent stages are joined together.

Abstract: A Schottky rectifier has multiple stages with substantially identical or very similar structures. Each stage includes a nitride-based semiconductor layer, a Schottky contact formed on one surface of the semiconductor layer, and an ohmic contact formed on an opposite surface of the semiconductor layer. The Schottky layer is formed from a metallic material with a high metal work function, and the ohmic contact is formed from a metallic material with a low metal work function. At least one of the stages is a middle stage located between two adjacent stages, such that the Schottky contact of the middle stage and the ohmic contact of one of the adjacent stages are joined together, and such that the ohmic contact of the middle stage and the Schottky contact of another one of the adjacent stages are joined together.

Abstract: A Schottky rectifier has multiple stages with substantially identical or very similar structures. Each stage includes a nitride-based semiconductor layer, a Schottky contact formed on one surface of the semiconductor layer, and an ohmic contact formed on an opposite surface of the semiconductor layer. The Schottky layer is formed from a metallic material with a high metal work function, and the ohmic contact is formed from a metallic material with a low metal work function. At least one of the stages is a middle stage located between two adjacent stages, such that the Schottky contact of the middle stage and the ohmic contact of one of the adjacent stages are joined together, and such that the ohmic contact of the middle stage and the Schottky contact of another one of the adjacent stages are joined together.

Abstract: High power thyristor-type devices comprising a first layer of p-type doped semiconductor alloy aluminum gallium nitride, a second layer of n-type doped aluminum gallium nitride with lower aluminum content than the first layer, a third layer of p-type doped aluminum gallium nitride with a higher aluminum content than the second layer, and a fourth layer of aluminum gallium nitride of n-type doping. The difference in hole and electron energies (band offsets) across the interface between aluminum gallium nitride and gallium nitride are such that hole and electron transfer are enhanced from aluminum gallium nitride to gallium nitride, or hole and electron transfer are suppressed from gallium nitride to aluminum gallium nitride. Aluminum content in layers 1 and 2 is chosen such that hole transfer in the forward biased conduction state of the device is enhanced, and suppressed in the reverse biased blocking state of the device.

Abstract: A Schottky high power rectifier having a nitride insulator formed on the surface of a GaN substrate. The nitride insulator increases the electric field breakdown suppression at or near the surface of the rectifier below the insulator. In a preferred embodiment, the nitride insulator is an epitaxially grown aluminum nitride insulator.