Abstract
The p + - and n + -Si channels were prepared by implanting a dose of 5 × 10 15 ions/cm 2 of BF + 2 and As + at 40 keV, respectively, into the n-Si and p-Si substrates, followed by a 900°C-30 min annealing. Nickel contacts (cathode and anode) to these channels were electron-gun evaporated. Electrical current was applied gradually to 80 mA to these channels, corresponding to current densities of 10 6 -10 7 A/cm 2 . For the p + -Si, the resistance responded by increasing to a maximum, then decreasing until a precipitous drop took place. For the n + -Si, the resistance increased by a less amount compared to the p + -Si, but also dropped abruptly. The resistance drop is permanent in the p + -Si channels, but not in the n + -Si channels. Mechanisms responsible for these resistance changes in terms of Joule heating, high field effect and junction leakage are proposed. For the precipitous drop in channel resistance of the p + -Si, scanning electron microscopy and transmission electron microscopy showed that a NiSi 2 line bridging the cathode and anode contacts had been formed. No silicide line formation in the n + -Si channels was observed. © 1998 American Institute of Physics.