STRESS IN SIO2-FILMS DEPOSITED BY PLASMA AND OZONE TETRAETHYLORTHOSILICATE CHEMICAL VAPOR-DEPOSITION PROCESSES

The behavior of stress was studied in as-deposited and thermal cycled SiO2 films deposited by plasma tetraethylorthosilicate (TEOS) and ozone TEOS chemical vapor deposition (CVD) processes. It was found that the stress is large and compressive for thin films (less-than-or-equal-to 1500 angstrom) for both types of oxides. At larger thicknesses, the stress becomes very small. During thermal cycling, the stress variation shows a hysteresis behavior. However, the type of hysteresis depends on the maximum temperature of cycling. This behavior of stress is explained based on the densification and structural changes in the oxide film which are shown up by the changes in the IR absorption spectra.