Photoluminescence analysis of annealing process in low-dose SIMOX wafers

A thin film silicon-on-insulator (SOI) wafer synthesized by separation by implantation of oxygen (SIMOX) is regarded as one of the most promising substrates for the next-generation low-power, high-speed, and highly integrated devices. Low-dose SIMOX in particular has the advantages of low defect density and low production cost. The method requires high-temperature annealing not only to eliminate implantation-induced defects but also to form a continuous buried oxide (BOX) layer by coalescence of oxygen precipitates (Nakashima and Izumi, 1993). Dislocations are generated from the precipitates during annealing, which are harmful for device performance. The behavior of dislocations and the other defects should, therefore, be accurately characterized to determine the appropriate dose and annealing conditions. In this study, we analyzed defects in low-dose SIMOX wafers by photoluminescence (PL) spectroscopy with ultraviolet (UV) laser light as an excitation source. This technique enabled us to measure the PL only from the superficial Si layer (Tajima and Ibuka, 1998; Tajima et al, 1998).