STRUCTURAL-CHANGE OF AMORPHOUS-SILICON INDUCED BY X-RAY-IRRADIATION FROM SYNCHROTRON-RADIATION

Using synchrotron radiation, amorphous silicon (a-Si) films were irrad iated by X-rays with photon energy large enough to excite K-shell elec trons in silicon. Electron spin resonance measurements showed that the effective formation efficiency of dangling bonds per X-ray photon was seven to eight orders of magnitude larger than that for the conventio nal light soaking using laser light. Photoconductivity and positron li fetime measurements indicated that, besides the dangling bonds, microv oid-like defects are induced by X-ray irradiation. The enhancement of the solid-phase crystallization of a-Si by X-ray irradiation is discus sed on the basis of such structural change.