Hi I have different combination of Si(x)Ge(1-x) and SixGe1-xOy with x having the value of 0.15, 0.30 and 0.40 and y having value starting from 0.03 to 17. My films are deposited on microscopic cover glass having 0.22 mm thickness by RF sputtering at 33 SCCM of Ar flow for 2 hours. My expected thickness is about 5-6 microns. I need to determine the exact thickness as well as the value of n and k. I did complete the transmission and reflection data using VASE made of J. Wollam, but those having too many spikes. Can any one help me how can I create a model for these kinds of thick samples and analyze the data? Thank you in advance. Mukti M Rana PhD. Student in Electrical Engineering The University of Texas at Arlington Room # 208, Nano Fab Center 500 Cooper St. , Box 19072 Arlington, TX 76019, USA Tel: (817) 272-1265 (Office) (817) 723-1090 (Cell)