Silicon carbide and SiCAlN heterojunction bipolar transistor structures

Abstract

A heterojunction bipolar transistor (HBT) structure is configured so that the heterojunction between hexagonal and cubic materials is electrically active. A first embodiment of the HBT structure comprises both hexagonal and cubic silicon carbide (SiC). The emitter region is fabricated from the higher bandgap hexagonal SiC appropriately doped. The base and collector regions are grown using the lower bandgap cubic SiC. A second embodiment of the HBT structure comprises both a solid solution of SiC material such as an alloy of silicon carbon aluminum nitrogen (SiCAlN) grown upon a substrate of hexagonal SiC. The emitter region can be placed either on the top or bottom of the second embodiment of the HBT structure. Also, the bandgap between the emitter and base regions of the second embodiment can be varied by controlling the mole fraction ratio between the constituent parts of the SiCAlN, i.e., between the SiC and the AlN.

Dependencies are inferred from the claim text.