Rapid thermal annealing effects on plasma deposited SiOx : H films

Abstract

The bonding configuration, hydrogen evolution and defect content of rapid thermally annealed (RTA) SiOx:H films of different initial compositions were studied. Infrared absorption measurements showed that all the hydrogen present in the films was lost at temperatures lower than 700degreesC without any change in the oxygen to silicon ratio of films. RTA temperatures higher than 700degreesC promote a change in the Si-O-Si stretching position from the initial unannealed value to the 1070-1080 cm(-1) range independent of the initial film composition. Electron Spin Resonance (ESR) measurements show that all the films contained two types of paramagnetic defects: E' (.SidropO(3)) and D (.SidropSi(3))Annealing up to 700degreesC promotes the disappearance of the E' centre. For films where the D defect is present (all except the film with x approximate to 2), the concentration of these defects initially decreases for annealing temperatures of 400degreesC, then continuously increases for temperatures up to 700degreesC, getting a saturation value in the 10(18)-10(19) cm(-3) range for higher temperatures. ESR characterisation suggests that annealing at higher temperatures promotes the formation of a high-quality SiO2 matrix in which Si nanocrystals are formed, the D defects being located within these nanocrystals.