AES ANALYSIS OF SILICON-NITRIDE FORMATION BY 10-KEV N-2(+) ION-IMPLANTATION( AND N)

Reactions of N+ and N-2(+) ions with the Si(100) surface as a function of ion dose and angle of incidence by 10 keV N+ and N-2(+) bombardmen t have been studied by in situ Auger electron spectroscopy (AES) analy sis. The AES measurements show that a continued exposure of the ion be am to a saturation dose of >5 x 10(16) N-2(+)/cm(2) leads to a surface stoichiometry close to that of Si3N4. Complete nitridation, i.e. the formation of Si3N4, could be achieved at incident angles between 0 deg rees and 30 degrees to the surface normal. At incident angles exceedin g 30 degrees the degree of nitridation decreases. Above 60 degrees inc ident angle, no nitride was found in the near-surface region. A simpli fied model has been proposed to explain the observed angular dependenc e. The samples with higher ion doses were also examined by ex situ sca nning electron microscopy (SEM). No blister or bubble was found on the surface suggesting that under saturation conditions the self-sputteri ng of captured nitrogen atoms near the surface by further incoming pro jectiles is the major contributor to nitrogen removal in our experimen t. No pronounced difference between N+ and N-2(+) bombardment was obse rved in this experiment. Copyright (C) 1996 Elsevier Science Ltd