THERMAL-DESORPTION AND INFRARED STUDIES OF PLASMA-ENHANCED CHEMICAL VAPOR-DEPOSITED SIO FILMS WITH TETRAETHYLORTHOSILICATE

Thermal desorption and Fourier transform infrared spectroscopies were used to study plasma-enhanced chemical vapor deposited SiO films from tetraethylorthosilicate. Significant water desorption and concomitant structural changes were observed for the films during subsequent heat treatments between 100 and 700-degrees-C. The films exhibited three di stinct water desorption states. The desorption temperatures were appro ximately 100-200-degrees-C for the first state, 150-300-degrees-C for the second state, and 350-650-degrees-C for the third state. Air expos ure experiments revealed that the first and second states resulted fro m absorbed water and the third state from constitution water. The firs t and second desorption states were confirmed to originate from liquid like water and water molecules hydrogen-bonded to Si-OH bonds at macr opore sites in the films, respectively. The third desorption state was found to result from Si-OH bonds formed during the film growth. This desorption of constitution water was considered to be accompanied by a microstructural change of the films.