OPTICAL-PROPERTIES OF PLASMA POLYMER-FILMS (HEXAMETHYLDISILOXANE)

Thin polymer films were deposited in an r.f. discharge of organic vapo ur (hexamethyldisiloxane (HMDSO)) in the pressure range 0.06-0.5 mbar. Plasma chemical gas conversion influences the deposition process and film properties, thereby producing a refractive index gradient in plas ma polymer films. The relationship between the gas composition of the plasma and the changes of resultant film properties was in situ analys ed by means of mass spectrometry and single-wavelength ellipsometry. T he refractive index of the silicon-organic polymer films varies from 1 .45 to above 2.0 over a thickness range of about 200 nm owing to chang es in the molecular structure. The dispersion behaviour of HMDSO plasm a polymer films and the depth profile of the refractive index were inv estigated by means of spectroscopic ellipsometry (300-800 nm). Additio nal investigations of the films confirm a change of film composition.