An amorphous SiC:H emitter heterojunction bipolar transistor

After confirming the successful application of the amorphous SiC:H(a-SiC:H)/crystalline Si(c-Si) heterostructure in a solar cell and considering its prospective application in Bi-CMOS devices, an attempt has been made to apply the same in the fabrication of a heterojunction bipolar transistor. A p-n-p heterojunction bipolar transistor with a wide band-gap boron-doped amorphous SiC:H emitter and crystalline Si (base, collector) has been realized and is reported here for the first time. Good device performance has been observed at the a-SiC:H deposition temperature of 450°C. Preliminary results gave a current gain,hFE(max)) of 50 at a current density of approximately 2.4 A/cm2(base dose 2 × 1012/cm2, width ≃ 0.4 µm). Temperature dependence of the transistorhFE-ICcharacteristics was also studied.