DETERMINATION OF OPTICAL DISPERSION AND FILM THICKNESS OF SEMICONDUCTING DISORDERED LAYERS BY TRANSMISSION MEASUREMENTS - APPLICATION FOR CHEMICALLY VAPOR-DEPOSITED SI AND SNO2 FILM

A method is presented for the determination of the optical dispersion and thickness of thin semiconducting disordered layers, or stacks of s uch layers, deposited on fully or partly transparent substrates using transmission measurements. The method consists in fitting to the exper imentally recorded spectra, theoretical ones, generated simulating thr optical dispersion of the films involved with the help of the physica l model proposed by Forouhi and Bloomer for amorphous semiconductors [ Phys. Rev. B 34, 7018 (1986)]. The fit is mode using standard regressi on analysis techniques that allow determination of the model parameter s corresponding to these films. This method is applied for amorphous S i layers deposited on fused silica substrates by low pressure chemical vapor deposition (CVD) and SnO2 films grown by atmospheric pressure C VD on glass substrates and give results that are in agreement with tho se reported in the literature. (C) 1997 American Institute of Physics.