Spatial rotational temperature and emission intensity profiles in silane plasmas

The spatial variation of the rotational temperature of the 0-0 band of the A transition of SiH in radio frequency pure silane discharges is investigated by utilizing a method of improved accuracy for the simulation of the emission spectrum. Furthermore, the variation of the rotational temperature as a function of the pressure at the maximum intensity position of the interelectrode space is examined. The results are used to extract information about the relative variations of the electron energy distribution function and the effective electron density in the interelectrode space. Thus, it is considered that there is a sensitive relation of the observed high rotational temperatures to the mean electron energy, provided that the electron energy distribution function does not change. More specifically, a decrease of the rotational temperature is observed on moving away from the powered electrode sheath region and a similar decrease is also detected with increasing pressure. This behaviour is compared with the spatial emission intensity profiles. The variation of the space-integrated emission intensity under the various discharge conditions, related to the modification of the effective electron density, is also presented.