USE OF AN ELECTRON-CYCLOTRON RESONANCE PLASMA SOURCE FOR SI(001)2 X-1 SURFACE NITRIDATION BY N2 - AN X-RAY PHOTOEMISSION-STUDY

An ultra-high vacuum compatible electron cyclotron resonance (ECR) plasma source is employed for the first time in studying the surface nitridation of Si(001)2 X 1 surfaces held at low substrate temperature (T(s)) with N-2. The exposure to the efficiently activated and dissociated nitrogen flux in the microwave plasma is not limited to the silicon surface but results in the formation of ultra-thin dielectric near-stoichiometric Si3N4 layers (approximately 20 angstrom) analyzed in situ by X-ray photoelectron spectroscopy (XPS). These films, without hydrogen content and silicon deposit, could easily be grown in a few minutes at room temperature and at relatively low working pressures (approximately 10(-4) mbar in the chamber). Comparatively, in order to reach similar thicknesses by conventional thermal nitridation with a more easily dissociable molecule than N-2, i.e. NH3, very much higher T(s) (700-degrees-C) and exposures (> 10(6) L) are needed. Therefore a considerable benefit in the growth kinetics is achieved at lower T(s) in using the ECR source without destroying the underlying Si substrate as checked by X-ray photoelectron diffraction (XPD).