Analysis of conduction mechanisms in annealed n-Si1-xCx : H/p-crystalline Si heterojunction diodes for different doping concentrations

We fabricated and characterized annealed n-type amorphous Si1-xCx on p-type crystalline silicon heterojunction diodes with three different base doping concentrations: N-A similar to 10(16), 10(18), and 10(20) cm(-3). The cond uction mechanisms were determined by analyzing the temperature dependence o f the current-voltage characteristics. The results show that the diodes wit h low doping concentrations (10(16) cm(-3)) are ideal, because the phosphor ous slightly diffuses into the crystalline silicon, whereas diodes with hig her doping concentrations (10(18)-10(20) cm(-3)) are dominated by multitunn eling capture emission. The increase in the base acceptor doping concentrat ion also causes excess current over the ideal diode current at low forward bias and an increase in the leakage reverse current. (C) 1999 American Inst itute of Physics. [S0021-8979(99)08902-1].