Transport characteristics of optically-excited and electrically-injected minority electrons across p-Si/n-SiC hetero-interfaces

We report on the photoresponse of p-Si/n-SiC heterojunctions and the electrical characteristics of SiC/Si hetero-junction bipolar transistors (HBTs), both of which are fabricated by bonding SiC and Si layers. We find that in the photoresponse measurements the square root of the quantum yield almost linearly depends on the photon energy and the absorption edge (1.2 v) is close to the bandgap of Si (1.12 eV), which implies that the achieved signal is attributed to the minority electrons optically excited in the p-Si layer and collected in the n-SiC layer across the hetero-interfaces. The characteristics of the SiC/Si HBTs reveal the common-base current gain α of « 0.9 for the base-collector bias voltage of 0 V at room temperature. These results indicate that SiC/Si hetero-interfaces are applicable for novel minority-carrier-based semiconductor devices.