Physics Journal of the Indonesian Physical Society
THICKNESS MEASUREMENT OF THIN SILICON DIOXIDE FILMS AS INSULATOR GATE ON MOS DEVICES BY ELLIPSOMETRY
Research Center for Electronics and Telecommunications LIPI, Jl. Cisitu no. 21/154 D, Bandung 40135, Indonesia
In this paper will be presented experimental results for the thickness of silicon dioxide on (111) silicon surfaces as an insulator gate on MOS devices by ellipsometry. Good thickness uniformity of gate-oxide is very important in MOSFET devices especially as design rules shrink to submicron range. For silicon dioxide (SiO2), the good flatness is important in the use of photolithography and as gate oxide. In this research, thickness homogeneity as measured and shown by standard deviation of average thickness and delta thickness of the maximum and minimum value. Data were obtained from meuserement using L115C Ellipsometer Gaertner Waferskan. Variation process such as temperatures, deposition time, variety of gases which was used, the gas flow etc. This thermal dry oxidation was carried out to achieve best flatness, started from the simplest one to the modified one. The aim of this research was to find process that gave good thickness uniformity. The best thickness uniformity is pass through the final process, that is dry oxidation process with TCE vapour addition by 20 cc/minute flow, annealing nitrogen gas flow is 9 slpm with process at 1000oC. Also the best result is by the resulting of deviation standard 2 angstrom and thickness delta 4 angstrom or average thickness about 400 angstrom tolerance (< 3%).