Ion Implantation of Impurities into Polycrystalline Silicon
The doping characteristics of polycrystalline silicon were observed by ion implantation of boron and phosphorus. The complicated conditions such as polycrystalline silicon film formation, doping and heat treatment were separated by the ion implantation for doping method. Obtained results were; (1) The sheet resistivity was decreased abruptly and was changed minimum to maximum values with annealing temperature. (2) The sheet resistivity was changed exponentially with implant dose and the gradient was -4.7. (3) The carrier mobility and the carrier activation ratio were increased with implant dose. (4) The activation energies were 0.23 to 0.06 eV corresponding to the implant dose. These results are explained that the trapping or the ejection of impurities from grain boundary and the obtained activation energies are interpreted as the potential barrier height at the grain boundary.
KeywordsCarrier Mobility Hall Mobility Polycrystalline Silicon Isochronal Annealing Potential Barrier Height
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