ION MIXING ENHANCED WAFER BONDING FOR SILICON-ON-INSULATOR STRUCTURES

Bonding of a 1360-nm-thick single crystalline silicon membrane onto an oxidized wafer was enhanced by ion mixing using 1250 keV N-14+ ion implantation. The oxidized wafer was covered by a thin, thermally grown oxide (134 nm) and implantation was performed either in random or in channeling directions through the membrane. Ion doses were in the range of 0.5 x 10(16) to 5 x 10(16) atoms/cm2. Implantation was followed by an annealing at 1000-degrees-C for 0.5 h in nitrogen gas to remove the radiation defects. Due to the effect of implantation, the bonding quality was very good in all cases. In addition, results of Rutherford backscattering spectroscopy and transmission electron microscopy showed that using channeled implantation with a dose of 0.5 x 10(16) atoms/cm2, the adherent silicon layer was of high quality (approximately 1.5 x 10(3) dislocations/cm2) and the interface remained sharp.