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: NA∼1016, 1018, and 1020 cm−3. The conduction mechanisms were determined by analyzing the temperature dependence of the current–voltage characteristics. The results show that the diodes with low doping concentrations (1016 cm−3) are ideal, because the phosphorous slightly diffuses into the crystalline silicon, whereas diodes with higher doping concentrations (1018–1020 cm−3) are dominated by multitunneling capture emission. The increase in the base acceptor doping concentration also causes excess current over the ideal diode current at low forward bias and an increase in the leakage reverse current.