SILICON INTERSTITIALS GENERATION DURING THE EXPOSURE OF SILICON TO HYDROGEN PLASMA

Interstitials in silicon can be produced by hydrogen ions through chem ical action and physical impact. To establish the relative importance of the two processes, wafers of single crystal silicon kept at a tempe rature of 250 degrees C were exposed to a hydrogen plasma, with and wi thout an accelerating voltage (500 V). As gettering centers interstiti al-type dislocation loops were made, before H exposure, by implanting 1.9 x 10(15) at. cm(-2) 110 keV P atoms and annealing at 1000 degrees C for 30 s. The analysis was performed using MeV ion channeling, elast ic recoil detection analysis and cross-section transmission electron m icroscopy. The results suggest that H is captured by the defects: in t he case of unbiased plasma, H goes in the region of the extrinsic defe cts, while in the case of biased plasma, H is trapped near the surface where the defects are produced by the energetic H ions themselves. In both cases the data are consistent with the formation of hydrogen nan oblisters with the subsequent breaking of silicon bonds and injection of silicon interstitials. The migration of interstitials occurs at a t emperature as low as 250 degrees C.