| |
| Heterostructure of hydrogenated nanocrystalline silicon (nc-Si:H) film with crystalline silicon (C-Si), as a promising system for Si microelectronic devices, has been attracted great interests. In present work, a phosphorous doped nc-Si:H film was deposited on p-type C-Si substrate, then a heterojunction of (n)nc-Si:H/(p)C-Si was fabricated to investigate the carrier transport. The carrier conduction was deduced by analyzing the temperature dependence of current–voltage characteristics and capacitance-voltage measurement at room temperature. The forward current can be assigned to carrier tunneling aided thermionic emission-recombination in the space charge region of heterojunction. The diode has low reverse leakage currents and high rectification ratios of about 105 at ±1.0 V under different temperatures. The reverse leakage current can be attributed to minority carrier tunneling across the depletion layer rather than majority carrier when the reverse applied bias is from 0 to -10 V. While the reverse current can be due to the Poole–Frenkel emission when the reverse applied bias is from –10 V to –22 V. However, the reverse current can be owing to carrier resonant tunneling at higher reverse applied bias (≥-22V) at 77K. Then the reverse current is obviously enhanced with increasing temperature and the tunneling behavior is covered by carrier thermal emission. Thus the breakdown mechanism is made up of both tunneling and thermal effect. |
|
| Keywords:Hydrogenated Nanocrystalline Silicon Film, Heterojunction, Carrier Transpor |
|
