An amorphous SiC:H emitter heterojunction bipolar transistor

Abstract

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, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h_{FE(\max)}</tex> ) of 50 at a current density of approximately 2.4 A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> (base dose 2 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</sup> /cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , width ≃ 0.4 µm). Temperature dependence of the transistor <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">h_{FE}-I_{C}</tex> characteristics was also studied.