In situ infrared ellipsometry study of the growth of hydrogenated amorphous carbon thin films

Infrared Fourier transform phase-modulated ellipsometry (FTPME) has been used as an in situ probe to study the structural and vibrational properties of thin films. To illustrate the performance of this technique, in situ (psi, Delta) measurements have been obtained during the growth of different types of hydrogenated amorphous carbon (a-C:H) films deposited from plasmas onto crystalline silicon (c-Si). The refractive index and thickness of the films have been determined through (psi, Delta) analysis over the CHn stretching region. Within this vibrational range, the chemical nature of the bonds formed during the growth can be identified. The role of ion bombardment and interlayer formation, which are both of crucial importance in a-C:H film properties, have been studied under soft plasma conditions. Through studies of the C-H vibrational intensity, a microstructure model can be given for a-C:H deposited at low ion bombardment. (C) 1998 Elsevier Science S.A.