Transistors and method for making ohmic contact to transistors

摘要

A transistor device having non-alloyed ohmic contacts formed by a process that improves the contact morphology and reduces metal spiking into the semiconductor layers. During fabrication, a regrowth mask is deposited on the semiconductor device. A portion of the regrowth mask and the epitaxial semiconductor layers is removed, defining areas for selective regrowth of a highly-doped semiconductor material. The remaining portion of the regrowth mask forms a regrowth mask residual layer. After regrowth, ohmic contacts are formed on the regrowth structures without the use of a high-temperature annealing process. The regrowth mask residual layer does not need to be removed, but rather remains on the device throughout fabrication and can function as a passivation layer and/or a spacer layer.

主权项

1. A transistor device, comprising:
at least one semiconductor layer; a regrowth mask residual layer on at least a portion of said at least one semiconductor layer, said regrowth mask residual layer comprising a gate trench; a plurality of regrowth structures comprising a highly doped semiconductor material, said regrowth structures on different portions of said at least one semiconductor layer than the portion covered by said regrowth mask residual layer, wherein a top surface of each of said regrowth structures is below a top surface of said at least one semiconductor layer, said regrowth structures on respective portions of said at least one semiconductor layer; a drain contact and a source contact, each disposed on a different one of said regrowth structures; a gate disposed on said regrowth mask residual layer and electrically coupled to said at least one semiconductor layer through said gate trench.