Carrier transport properties of the (n)nc-Si : H/(p)c-Si heterojunction

Phosphor-doped nano-crystalline silicon ((n))nc-Si:H) films are successfull y grown on the p-type (100) oriented crystal silicon ((p) c-Si) substrate b y conventional plasma-enhanced chemical vapor deposition method. The films are obtained using high H-2 diluted SiH4 as a reaction gas source and using PH3 as the doping gas source of phosphor atoms. Futhermore, the heterojunc tion diodes are also fabricated by using (n)nc-Si:H films and (p)c-Si subst rate. I-V properties are investigated in the temperature range of 230-420K. The experimental results domenstrate that (n)nc-Si:H/(p) c-Si heterojuncti on is a typical abrupt heterojunction having good rectifing and temperature properties. Carrier transport mechanisms are tunneling - recombination mod el at forward bias voltages. In the range of low bias voltages ( V-F< 0.8 V ), the current is determined by recombination at the (n)nc-Si:H side of the space charge region, while the current becomes tunneing at higher bias vol tages( V-F>1.0 V). The present heterojunction has high reverse breakdown vo ltage ( > - 75 V) and low reverse current (approximate to nA).