Annealing behaviour of high-dose-implanted nitrogen in InP

Concentration profiles of nitrogen in vacuum-annealed p- and n-type single-crystal (1 0 0) InP implanted with 1 × 10¹⁶ 30 keV¹⁵N⁺ ions cm⁻² have been studied by Secondary Ion Mass Spectrometry (SIMS) and Nuclear Resonance Broadening (NRB) techniques. Damage induced by the nitrogen implantation was studied by Rutherford Backscattering Spectrometry (RBS) and channeling. Annealing the samples led to loss and redistribution of nitrogen in the temperature range from 575 to 675 °C. At temperatures from 575 to 600 °C, rapid migration of nitrogen towards the sample surface was observed. The n-type InP material had a very dominant tendency for surface nitrogen build-up, whereas the p-type material had a markedly smaller surface peak in the nitrogen distribution. The surface peak in n-type material is due to sulphur acting partly as a diffusion barrier. SIMS analyses showed sulphur build-up on the surface in the course of annealing. At temperatures from 600 to 675 °C, the nitrogen profiles of n- and p-type InP were similar. A small loss of nitrogen was observed at 625–675 °C. Two different recovery stages were observed at 575–600°C and at 625–650 °C. The corresponding activation energies for nitrogen loss are 2.9 and 3.0 eV, respectively.