ELECTRICAL CHARACTERIZATION OF N-AMORPHOUS P-CRYSTALLINE SILICON HETEROJUNCTIONS/

n-type amorphous silicon on p-type crystalline silicon heterojunction diodes were fabricated and electrically characterized. The a-Si:H film was deposited by plasma enhanced chemical vapor deposition. Electrica l properties were investigated by capacitance-voltage and current-volt age measurements at different temperatures. The capacitance-voltage re sults confirm an abrupt heterojunction. Current-voltage characteristic s show good rectifying properties (50000:1 at +/-0.5 V). A detailed an alysis of transport mechanisms was developed in order to establish a u nified model of conduction. Two carrier transport mechanisms are belie ved to be at the origin of the forward current. At low bias voltage (V <0.4 V), the current is determined by recombination at the amorphous s ide of the space charge region, while at higher voltages (V>0.6 V), th e current becomes space charge limited. (C) 1996 American Institute of Physics.