Dopant activation occurs via both thermal annealing and lighthyphen;soaking in boronhyphen;doped hydrogenated amorphous siliconndash;carbon prepared at a relatively low temperature. Both kinds of dopant activation probably originate from the same boron sites, because they both cause almost the same increase in dark conductivity, and no lighthyphen;induced activation occurs after the thermally induced activation has been attained. The lighthyphen;induced states show relaxation even at room temperature and are bistable sites, but the thermally induced states show no significant relaxation and have a more stable configuration. Perhaps, the lighthyphen;induced states are caused by microscopic change and the thermally induced states are created with larger scale restructuring. copy;1996 American Institute of Physics.
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