TY - JOUR
T1 - Characterization of pulsed-laser deposited amorphous diamond films by spectroscopic ellipsometry
AU - Jellison, G. E.
AU - Geohegan, D. B.
AU - Lowndes, D. H.
AU - Puretzky, A. A.
AU - Merkulov, V. I.
PY - 1998
Y1 - 1998
N2 - Spectroscopic ellipsometry is used to characterize amorphous diamond, also known as tetrahedral amorphous carbon, (ta-C) films grown by pulsed laser ablation. The ellipsometry data is collected with the two-modulator generalized ellipsometer, which measures all three parameters required to characterize isotropic samples, as well as additional parameters used to characterize strain-induced birefringence of the focusing optics. Lenses are used to focus the light spot to an ellipse 0.7×2.0 mm2, allowing us to perform several ellipsometric measurements across the profile of ta-C films grown on 7.5 cm diameter Si wafers. The spectroscopic ellipsometry data are fit using a model of the ta-C dielectric function based on the Tauc band edge and the Lorentz expression of the dielectric function for an ensemble of atoms. These fits are used to determine the thicknesses of the rough surface layer, the ta-C film, and the interface layer, as well as the energy gap of the film. Comparisons are made with fits to an earlier formulation due to Forouhi and Bloomer. In addition to being Kramer-Kronig consistent, the Tauc-Lorentz formulation fits the ta-C data better.
AB - Spectroscopic ellipsometry is used to characterize amorphous diamond, also known as tetrahedral amorphous carbon, (ta-C) films grown by pulsed laser ablation. The ellipsometry data is collected with the two-modulator generalized ellipsometer, which measures all three parameters required to characterize isotropic samples, as well as additional parameters used to characterize strain-induced birefringence of the focusing optics. Lenses are used to focus the light spot to an ellipse 0.7×2.0 mm2, allowing us to perform several ellipsometric measurements across the profile of ta-C films grown on 7.5 cm diameter Si wafers. The spectroscopic ellipsometry data are fit using a model of the ta-C dielectric function based on the Tauc band edge and the Lorentz expression of the dielectric function for an ensemble of atoms. These fits are used to determine the thicknesses of the rough surface layer, the ta-C film, and the interface layer, as well as the energy gap of the film. Comparisons are made with fits to an earlier formulation due to Forouhi and Bloomer. In addition to being Kramer-Kronig consistent, the Tauc-Lorentz formulation fits the ta-C data better.
UR - http://www.scopus.com/inward/record.url?scp=0032316320&partnerID=8YFLogxK
U2 - 10.1557/proc-526-349
DO - 10.1557/proc-526-349
M3 - Conference article
AN - SCOPUS:0032316320
SN - 0272-9172
VL - 526
SP - 349
EP - 354
JO - Materials Research Society Symposium - Proceedings
JF - Materials Research Society Symposium - Proceedings
T2 - Proceedings of the 1998 MRS Spring Meeting
Y2 - 13 April 1998 through 16 April 1998
ER -