Abstract: A semiconductor device with ohmic contact is provided with a method of making the same. In one embodiment, a method is provided for fabricating a semiconductor device. The method comprises providing a semiconductor structure with a N-type doped semiconductor contact layer, forming a platinum contact portion over the N-type doped semiconductor contact layer, forming an adhesive contact portion over the platinum contact portion, forming a barrier contact portion over the adhesive contact portion, and forming a gold contact portion over the barrier contact portion. The method further comprises annealing the semiconductor structure to alloy the platinum contact portion with the N-type doped semiconductor contact layer to form a platinum/semiconductor alloyed diffusion contact barrier substantially disposed within the N-type doped semiconductor contact layer.

Abstract: A semiconductor device (100) is formed on a semi-insulating semiconductor substrate (101) including a channel layer (104), a spacer layer (105), an electron supply layer (106), and a barrier layer (108). A composite layer (110) is formed over the barrier layer (108). A metal (116) is deposited over the composite layer (110). The metal (116) is annealed to promote a chemical reaction between the metal (116) and the composite layer (110) in which a portion of the metal sinks into the composite layer (110) and forms an ohmic contact with the composite layer.

Abstract: An NPN double heterostructure bipolar transistor (DHBT) is disclosed with a base region comprising a layer of p-type-doped indium gallium arsenide nitride (InGaAsN) sandwiched between n-type-doped collector and emitter regions. The use of InGaAsN for the base region lowers the transistor turn-on voltage, Von, thereby reducing power dissipation within the device. The NPN transistor, which has applications for forming low-power electronic circuitry, is formed on a gallium arsenide (GaAs) substrate and can be fabricated at commercial GaAs foundries. Methods for fabricating the NPN transistor are also disclosed.