Abstract: A heterojunction bipolar transistor (HBT) structure with GaPSbAs base is disclosed. The HBT structure generally includes a substrate, a subcollector layer, a collector layer, a base layer, an emitter layer, an emitter cap layer, and a contact layer laminated from bottom to top sequentially, and optionally may further comprise a buffer layer between the substrate and the subcollector layer. The subcollector layer includes heavily-doped GaAs; the collector layer includes GaAs, InGaP, or AlGaAs; the base layer includes GaPAsSb compound; the emitter layer includes InGaP or AlGaAs; the emitter cap layer includes GaAs; the contact layer includes InGaAs; and the substrate includes semi-insulating GaAs. Since the base having GaPSbAs compound has lower band gap energy, the turn-on voltage of the transistors can be reduced.

Abstract: The HBT-based transient suppression device contains a collector layer of a first conduction type, a base layer of a second conduction type, an emitter layer of the first conduction type, stacked in this order sequentially on a top side of a heavily doped substrate of the first conduction type. The doping concentration of the base layer is higher than that of the emitter and collector layers, and that the thickness of the collector layer is less than 300 nm, so that the BVCEO breakdown voltage is reduced below 5V Additionally, the thickness of the base layer is larger than the sum of the thickness of a section of the emitter-base depletion region extending into the base layer and the thickness of a section of the base-collector depletion region extending into the base layer, so that the base layer is not operated in a punch-through condition.

Abstract: The invention provides a BiFET semiconductor device vertically integrating a FET and a HBT on the same substrate. The BiFET semiconductor device comprises a HBT structure, a high-resistivity structure, and a FET structure, sequentially formed in this order from bottom to top on a semi-insulating substrate. The high-resistivity structure comprises at least two layers. A first layer is on top of the HBT structure to provide the required high resistivity, while the second layer having a high purity is on top of the first layer to prevent the doped impurity in the first layer to affect the upper FET structure.

Abstract: A material made by arranging layers of gallium-arsenide-antimonide (GaAsxSb1-x, 0.0?x?1.0) and/or indium-gallium-arsenic-nitride (InyGa1-yAszN1-z, 0.0?y, z?1.0) in a specific order is used to form the transistor base of a heterojunction bipolar transistor. By controlling the compositions of the materials indium-gallium-arsenic-nitride and gallium-arsenide-antimonide, and by changing the thickness and order of the layers, the new material would possess a specific energy gap, which in turn determines the base-emitter turn-on voltage of the heterojunction bipolar transistor.

Abstract: The invention provides a BiFET semiconductor device vertically integrating a FET and a HBT on the same substrate. The BiFET semiconductor device comprises a HBT structure, a high-resistivity structure, and a FET structure, sequentially formed in this order from bottom to top on a semi-insulating substrate. The high-resistivity structure comprises at least two layers. A first layer is on top of the HBT structure to provide the required high resistivity, while the second layer having a high purity is on top of the first layer to prevent the doped impurity in the first layer to affect the upper FET structure.

Abstract: A material made by arranging layers of gallium-arsenide-antimonide (GaAsxSb1?x, 0.0?x?1.0) and/or indium-gallium-arsenic-nitride (InyGa1?yAszN1?z, 0.0?y, z?1.0) in a specific order is used to form the transistor base of a heterojunction bipolar transistor. By controlling the compositions of the materials indium-gallium-arsenic-nitride and gallium-arsenide-antimonide, and by changing the thickness and order of the layers, the new material would possess a specific energy gap, which in turn determines the base-emitter turn-on voltage of the heterojunction bipolar transistor.