Theoretical study of the influence of strain and polarization on performance of AlGaN/4H-SiC HBT

The n+-AlGaN/p+-4H-SiC/n-4H-SiC HBT structure possesses large interfacial polarization charges as well as bulk and interfacial defects. Considerable leakage currents have thus far prevented significant development of this device. The piezoelectric polarization charge can be controlled by modifying the strain in the structure and can in fact negate the spontaneous charge for an Al0.3Ga0.7N layer on 4H-SiC. Although large-area AlGaN films are …