Remote microwave plasma enhanced chemical vapour deposition of SiO2 films: oxygen plasma diagnostic

Abstract

Silicon oxide is deposited by remote microwave plasma enhanced chemical vapour deposition (RMPECVD). The silica films are produced by exciting oxygen in a microwave discharge while a mixture of 5% of silane diluted in argon is introduced downstream. In the afterglow, double Langmuir probe measurements and rotational temperatures deduced from optical emission spectroscopy (OES), show that the electron energy is transferred to the gas when the pressure increases (19 - 26 Pa). Therefore the electronic temperature decreases from 22000 to 11000 K and the gas temperature increases from 400 to 500 K. Moreover the microwave power (180 -480 W) has an influence on the deposition rate and on the quality of SiO 2 coatings (density and etch rate in an HF solution). This effect can be correlated with the increase in the electron density (0.7.10 10 to 3.7.10 10 cm -3 ) and of the gas temperature (400 to 460 K).