Annihilation and formation of electron traps in hydrogen-implanted n-type silicon by light illumination

Abstract

Annihilation and formation of electron traps by light illumination in 170-keV-hydrogen-implanted n-type silicon with a dose of 2×1010 cm−2 has been studied with deep level transient spectroscopy for fabricated gold Schottky diodes. In addition to the well-known vacancy-related traps (A center, divacancy and E center), two hydrogen-related E(0.32) and E(0.49) traps are produced by hydrogen implantation. It is found in zero-biased diodes that the partial annihilation of vacancy-related traps and corresponding formation of hydrogen-related traps occurs with illumination of light with photon energy above the band-gap energy. No effects of light illumination are found in reverse-biased diodes. The partial annihilation of vacancy-related defects is caused by the complex formation with hydrogen which is liberated from shallow-level, hydrogen-containing defects other than the E(0.32) and E(0.49) traps. The hydrogen liberation is thought to occur through induced instability of hydrogen-containing defects by changing their charge states with electron capture. The hydrogen-related E(0.32) trap is ascribed to the complex of the A center and hydrogen.