PtSi/n-type Si Schottky barrier height change by H + ion implantation near the interface region

Abstract

PtSi/n-type Si Schottky diodes were implanted with hydrogen ions of 150 keV energy in order for the peak of the hydrogen distribution to be localized near the silicide-semiconductor interface. Following implantation at doses between 1 × 1017 H/cm2 and 5 × 1017 H/cm2, C-V measurements indicated that the barrier height had increased from 0.84 eV to ≈ 1.10 eV. One possible explanation for the increase in barrier height is hydrogen passivation of the surface states at the silicide-silicon interface. I-V measurements indicated that the leakage current had increased by a factor of nearly 10, as compared to the unimplanted case. The samples which had been implanted at a dose of 5 × 1017 H/cm2 were annealed in a nitrogen ambient at 200° C for 30 min, while those implanted at 1 × 1017 H/cm2 were subjected to a “Rapid Thermal Annealing” step at 450° C for 10 s. C-V measurements revealed that the barrier height value had nearly reverted to that of the unimplanted case. In addition, I- V measurements did not show any significant change in the leakage current, therefore most of the damage was observed to be still present following the annealing step. Based upon the fact that the damage had not yet been annealed, and that the barrier height had nearly reverted to its original value, it is proposed that the hydrogen atoms responsible for the increase in the value of the barrier height had diffused out of the interface region upon heat treatment.