Electrically active defects in surface preamorphized and subsequently RTP-annealed Si and the effect of titanium silicidation

Thermal evolution of ion implantation-induced defects and the influence of concurrent titanium silicidation in pre-amorphized p-type Si (implanted with 25 KeV, 10¹⁶ cm^-2 Si⁺) under rapid thermal processing (RTP) have been studied. Ion implantation-induced electrically active defects have been detected by deep level transient spectroscopy (DLTS), capacitance-temperature (C-T), and spreading resistance measurements. DLTS characterization results show that the thermal evolution of electrically active defects in self-ion (Si⁺) implanted Si depends critically on the post-implantation thermal anneal: Hole traps H₁(0.33 eV) and H₄(0.47 eV) appear after the highest temperature (950 °C) RTP anneal, while a single trap H₃(0.26 eV) level shows up at lower anneal temperatures (≤900 °C). The thermal signature of H₄ defect is very similar to that of iron interstitial while those of H₁ and H₃ levels appear to originate from some interstitial-related defects, possibly complexes. A complete elimination of the above interstitial-related defects with concurrent RTP Ti silicidation has been observed, apparently a result of vacancy injection. The paper will present details of defect evolution under various conditions of RTP for samples with and without the silicidation.