It was noted that a number of unusual phenomena, with regard to the diffusion and segregation of dopants in Si-on-insulator constructs, had yet to be explained. In the present study, SOITEC wafers were thinned to 700 and 1600Å by using oxidation and etching. Ion implantation was performed into Si-on-insulator and bulk Si wafers by using 11B+ ions at 6.5 and 19keV to a dose of 3 x 1014/cm2. Thermal processing occurred in a furnace at 750C, for times ranging from 300s to 8h, under an inert ambient. Using quantitative transmission electron microscopy it was observed that the concentration of trapped interstitials and the density of {311} defects was significantly reduced in Si-on-insulator constructs as compared to the bulk. The Hall effect was used to monitor the activation process of B in the Si-on-insulator and in bulk Si. Significantly less activation was observed in the Si-on-insulator, as compared to the bulk, and was dependent upon the surface Si thickness. For the first time, a decrease in the trapped interstitial concentration was observed in the Si-on-insulator; even with minimal dose loss to the buried oxide. It was proposed that the formation of B–interstitial clusters could be more pronounced in the Si-on-insulator, leading to a reduction in the trapped interstitial population and the {311} defect density.

Secondary Defect Formation in Bonded Silicon-on-Insulator after Boron Implantation. A.F.Saavedra, A.C.King, K.S.Jones, E.C.Jones, K.K.Chan: Journal of Vacuum Science & Technology B, 2004, 22[1], 459-62