IN-SITU INFRARED ELLIPSOMETRY STUDY OF THE GROWTH OF HYDROGENATED AMORPHOUS-CARBON THIN-FILMS

Infrared Fourier transform phase-modulated ellipsometry (FTPME) has be en used as an in situ probe to study the structural and vibrational pr operties of thin films. To illustrate the performance of this techniqu e, in situ (psi, Delta) measurements have been obtained during the gro wth 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, D elta) 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, w hich are both of crucial importance in a-C:H film properties, have bee n studied under soft plasma conditions. Through studies of the C-H vib rational intensity, a microstructure model can be given for a-C:H depo sited at low ion bombardment. (C) 1998 Elsevier Science S.A.