Impact of Acceptor Concentration on Electronic Properties of n+-GaN/p+-SiC Heterojunction for GaN/SiC Heterojunction Bipolar Transistor
The electrical properties of n+-GaN/p+-SiC heterojunction diodes have been investigated by varying the acceptor concentration of p+-SiC epilayers (Na) and polytype of SiC (4H- and 6H-SiC). The current-voltage (I-V) characteristics of diodes with Na ~ 1x1019 cm-3 were dominated by tunneling-assisted current. The diodes with Na ~ 1x1018 cm-3 exhibit excellent characteristics and 6H-SiC may be a better choice from a view point of electron injection into p-SiC base. Compared to previous investigations (Na<1016cm-3), we could obtain good rectification with p-SiC doped to two-order-of-magnitude higher acceptor concentration.
N. Wright, C.M. Johnson, K. Vassilevski, I. Nikitina and A. Horsfall
K. Amari et al., "Impact of Acceptor Concentration on Electronic Properties of n+-GaN/p+-SiC Heterojunction for GaN/SiC Heterojunction Bipolar Transistor", Materials Science Forum, Vols. 556-557, pp. 1039-1042, 2007