Real time spectroscopic ellipsometry on ultrathin (

Real time spectroscopic ellipsometry was used to det. the time evolution of the dielec. function, bulk thickness, and surface roughness during hot-wire chem. vapor deposition of hydrogenated amorphous silicon (a-Si:H). The amorphous silicon films were deposited on native-oxide-covered c-Si(100) and GaAs(100) substrates at temps. in the range from 70 to 350 DegC. Data anal. by a three layer optical model, consisting of substrate, bulk, and surface roughness layer, revealed that the dielec. function of the a-Si:H film changes in the initial growth regime (