Electron diffraction study of the structure of boron-and phosphorus-doped hydrogenated amorphous silicon

The effect of gas-phase doping with boron and phosphorus on the structure of glow-discharge amorphous hydrogenated silicon has been studied by means of energy-filtered electron diffraction. The reduced density function was calculated and the network was found to contract upon doping. At levels of less than 20 at.% neither boron nor phosphorus segregated from the network. At high phosphorus doping levels an amorphous chemically ordered structure corresponding to Si 2 P was formed. At high boron doping levels, evidence for the presence of boron icosahedra was obtained.