Investigation on deep level defects in rapid thermal annealed undoped n-type InP

Abstract

Deep levels in rapid thermal annealed Pd/n-InP Schottky contacts have been studied using deep level transient spectroscopy. It is observed that the as-deposited Pd/n-InP Schottky sample exhibit two deep levels with activation energies of 0.53 and 0.70 eV. In samples annealed at 400 °C, three deep levels having activation energies 0.18, 0.30 and 0.86 eV below the conduction band are observed and for samples annealed at 500 °C, four deep levels with activation energies 0.33, 0.44, 0.70 and 0.82 eV are observed. Fourier transform infrared spectroscopy measurements have been carried out on undoped as-deposited and annealed InP wafers at 300, 400 and 500 °C. The measurements revealed high concentration of hydrogen complexes in the form of VInH4 existing in InP wafer. The results show that VInH4 complex annihilates with increase of annealing temperature and results in the formation of P In 2+ and V P + defects at 0.70 and 0.44 eV, respectively.