HIGH-QUALITY LOW-TEMPERATURE DPECVD SILICON DIOXIDE

In this work we present the results on silicon dioxide films grown by the direct plasma enhanced chemical vapor deposition (DPECVD) techniqu e at low temperature (< 400 degrees C). The films were obtained by dec omposition of appropriate mixtures of silane and nitrous oxide under d ifferent deposition conditions and their optical and structural proper ties were analyzed through Fourier transform infrared spectroscopy and ellipsometry. The results demonstrate the feasibility of obtaining st oichiometric silicon dioxide thin films by DPECVD without traces (with in the detection limits of the FTIR analysis) of OH, NH or SiH bonds, provided suitable deposition conditions are utilized. In particular we show that DPECVD combined with small silane flow and small deposition pressure is as effective as the techniques already reported in the li terature, such as helium dilution or remote plasma CVD, in promoting t he growth of stoichiometric films structurally similar to thermally gr own silicon dioxide and having the added advantage of simplicity.