Thin ORMOSIL films with different organics

Structural, optical and electrical properties of silicate films modified by structure fragments containing different organic groups were studied. The ORMOSILs were produced by a cohydrolysis of tetraethoxysilane with differen t types of alkyl (aryl) substituted alkoxysilanes. Film structure and its e volution during heat treatment were studied by ellipsometry and IR spectros copy. For methyl- and phenyl-modified silicate films the shrinkage is lower than for silicate ones in the range of annealing temperature from 200 to 5 00 degrees C. The shrinkage of phenyl-modified silicate film is more than t hree times lower than of methyl- and trimethyl-modified ones. The presence of single or double C=C bonds in the organic chain leads to an increase in the film shrinkage due to the thermodestruction of the bond as it is confir med by IR data. In the case of phenyl- and methyl-modified silicate films t his process starts from 500 degrees C and it is accompanied by abrupt film shrinkage. The dielectric constant and the loss tangent of methyl and pheny l groups decrease due to reduction of hydroxyl content and film density. Ot her groups are not effective due to their thermodestruction at lower temper atures.