Deep and shallow levels in n-type indium phosphide irradiated with 200-keV deuterons

Abstract

A predominant deep level was found to have been introduced by a fluence of 1012 cm−2 into nominally undoped vapor phase epitaxial material having a carrier concentration of 2×1015 cm−3. The defect was formed up to but not including the end of range and was named a D center. The D-center concentration was ∼1×1016 cm−3, its electron emission activation energy was 0.40 eV, and it was activated at room temperature. In addition, shallow donor levels were formed as a result of the irradiation. An increased electron concentration of ∼1×1016 cm−3 due to these shallow donor levels was measured in the end of range, and we inferred their existence throughout the ion range. Via a Monte Carlo simulation of the ion bombardment, the region in front of the end of range and the end of range itself were found to be differentiated by the amounts of nuclear and electronic energies deposited in them. A model based on the D center being an acceptor can explain the observed results and is also consistent with the compensation known to result from light ion bombardment. We conclude from this model that the entire region between the surface and the end of range can be made highly resistive as a result of deuteron bombardment. Results of capacitance-voltage, capacitance and admittance deep level spectroscopy, and constant-capacitance measurements made on gold Schottky diodes are presented.