A study of the effect of ultraviolet (UV) and vacuum ultraviolet (VUV) photons on the minority carrier lifetime of single crystal silicon processed by rapid thermal and rapid photothermal processing

Minority carrier Lifetime is an efficient indicator of defect levels presen t in the starting material as well as process and equipment induced defects . By employing rapid thermal processing (RTP) and rapid photothermal proces sing (RPP) as the thermal processing techniques, we have studied the effect of ultraviolet (UV) and vacuum ultraviolet (VUV) photons on the bulk minor ity carrier lifetime of phosphorous doped and undoped single crystal silico n wafers. For both diffused and undiffused wafers, we have observed an enha ncement in the minority carrier Lifetime when UV and VUV photons are used i n conjunction with the samples processed without the use of UV and VUV phot ons. The effect of ramp rates on the minority carrier Lifetime and the sign ificance of optimized thermal cycles have also been studied in this paper. A possible explanation based on the dependence of diffusion coefficient on the photo spectrum of light source is also given in this paper.