Effects of trace nickel on the growth kinetics and the electrical characteristics of metal-induced laterally crystallized polycrystalline silicon and devices

An increase in the rate of nickel-based metal-induced lateral crystallization (MILC) of amorphous-silicon ( a-Si) was observed when the length of an a-Si island was decreased or, for a given island length, when an extra crystallization-inducing window was added. With phosphorus implanted in a localized region offset from the MILC front on the a-Si side, a slight reduction in the MILC rate was also observed. Nickel incorporated in a-Si beyond the MILC front is believed to be responsible for these effects. A diffusion coefficient of similar to 4 x 10(-8) cm(2)/sec was estimated for nickel in a-Si at 600 degrees C. An extended low- temperature anneal performed subsequent to the formation of MILC polycrystalline silicon led to a higher effective mobility and a lower off-state leakage current. If the anneal was performed in the presence of a phosphorus-implanted region, the leakage current could be further reduced but the activation of subsequently implanted phosphorus was hindered. The same was not observed for the activation of subsequently implanted boron.