A Novel Scheme for the Deposition and Spectroscopic Ellipsometry Characterization of PecVD, Silicon-based, Dielectric Layers for Optoelectronics Applications
Donald Agresta and Thomas Nelson
Sensors Directorate, Air Force Research Laboratory
(937) 255-1874 ext. 3365
Keywords: PecVD, Ellipsometry, Dielectric DBR, VCSEL
A novel scheme for the PecVD deposition and variable-angle spectroscopic ellipsometry (VASE) characterization of silicon-based dielectrics for both, electronic and optical device application, is described. Depending on the application, different sensitivity and accuracy requirements will be placed on the VASE measurements and subsequent data analysis. As example, we consider dielectric distributed-Bragg reflectors (DBRs) for 980-nm wavelength, vertical-cavity surface-emitting lasers. Pitfalls associated with the nonlinear least-squares method used to extract the physical parameters from the raw ellipsometry data are reviewed. Shortcomings of the widely used Cauchy model for film visible-near infrared dispersion are indicated. Suggestions for improving the confidence of the ellipsometer results are discussed.