THE EFFECT OF HYDROGEN DILUTION ON THE INTERATOMIC BONDING OF AMORPHOUS HYDROGENATED SILICON - CARBON

The effect of hydrogen dilution of the precursor gas mixture on the lo cal bonding environment in glow-discharge deposited a-Si:C:H has been studied by neutron diffraction and inelastic neutron scattering. The n eutron diffraction results show a large increase in the silicon-carbon bonding upon hydrogen dilution, at the expense of silicon-silicon bon ding. The inelastic neutron scattering provides complementary informat ion on the hydrogen bonding environment. The hydrogen is predominantly bonded in SiH and SiH2 groups, with a large increase in the SiH2 grou p concentration occurring upon hydrogen dilution. The data presented h ere show that SiH3 and CH(n) groups are present as a very small fracti on of H bonding sites, if at all.