ELECTROLUMINESCENCE FROM MECHANICALLY DAMAGED OXIDIZED SILICON

We have found significant electroluminescence (EL), clearly visible in room light, to be produced from lightly oxidized Si wafers, which hav e been mechanically scratched, or indented with a diamond tip. The EL occurs in the visible and infrared ranges. Undamaged oxidized samples, where the oxide is chemically thinned to allow current from a top con tact to pass, also show similar EL. However, damaged Si wafers that ha ve only normal thin or no oxide, show negligible EL. A search for quan tum-confined particles in indentation pits by scanning tunneling micro scopy does not show any present. The results point strongly to the EL mechanism being related to the damage creating areas of optimum oxide thickness. The results are compared with those from spark-processed an d laser-grooved silicon. (C) 1998 American Institute of Physics.