Ion Implantation-Induced Defects and the Influence of Titanium Silicidation

Abstract

AbstractThermal evolution of ion implantation-induced defects and the influence of concurrent titanium silicidation in pre-amorphized p-type Si (implanted with 25 KeV, 1016 cm2Si+) under rapid thermal processing (RTP) have been investigated. Presence of implantation-induced electrically active defects has been confirmed by current-voltage (IV) and deep level transient spectroscopy (DLTS) measurements. DLTS characterization results show that the evolution of electrically active defects in the Si implanted samples under RTP depend critically on the RTP temperature: Hole traps HI (0.33 eV) and H4 (0.47 eV) appear after the highest temperature (950 °C) anneal, while a single trap H3 (0.26 eV) shows up at lower anneal temperatures (≤ 900 °C). The thermal signature of H4 defect is very similar to that of the iron interstitial while those of HI and H3 levels appear to originate from some interstitial-related defects, possibly complexes. A most interesting finding is that the above interstitial related defects can be eliminated completely with Ti silicidation, apparently a result of vacancy injection. However the silicidation process itself introduces a new H2 (0.30 eV) level, albeit at much lower concentration. This same H2 level is also seen in unimplanted samples under RTP. The paper will present details of defect evolution under various conditions of RTP for samples with and without the self-implantation and silicidation.