Doping dependence of crystallization growth rate in a-Si CVD films

Abstract Crystallization growth rates (V g ) on boron and phosphorus doped a-Si C VD films are obtained using conductivity measurements during isothermal annealings at temperatures 510 A C . For boron doping, the associated activation energy of V g is equal to 2.9 eV in the whole doping range (up to 2 × 10 −3 B 2 H 6 ), whereas V g increases by a factor 4 in the range 0 − 7 × 10 −6 and remains almost constant for higher doping. In this low range, the neutral dangling bonds became positively charged and non paramagnetic by electronic compensation with the acceptors, and the E.S.R. signal decreases from 10 19 to 10 17 cm −3 . These results indicate clearly that dangling bonds and their charge state play an important role in the growth rate process.