Transient annealing of ion implanted indium phosphide

Abstract

A graphite strip heater and a multiply scanned electron beam have been used to anneal selenium implanted InP. The selenium dose ranged between 5×10 12 and 1×10 15 ions cm -2, and the ion energy was 200 keV and all implants were performed into semi-insulating substrates at room temperature. The power density for the e-beam irradiations varied from 8 to 165 W cm -2 corresponding to temperatures up to 1100°C; a fixed temperature of 700°C was used for the graphite strip heater anneals. The majority of samples were coated with about 0.1 μm of pyrolytically deposited Si 3N 4 at 550°C, however some uncapped samples were also studied. Uncapped samples could not be electrically activated with the e-beam, but a capped low dose, 5×10 12 cm -2, implant gave the best electrical activity of 17%. High percentage activities were obtained at higher doses, for example, a dose of 3.6×10 14 cm -2 produced an electrical activity of 36% with a sheet mobility of 760 cm 2 V -1 s -1. A similar dose, 5×10 14 cm -2, annealed using the graphite strip heater had an electrical activity of 34% and a sheet mobility of 760 cm 2 V -1 s -1. A lower dose, 1×10 13 cm -2 annealed with the graphite strip heater gave a maximum activity of 43% with a sheet mobility of 1400 cm 2 V -1 s -1. We have also found that the Si 3N 4 deposition process at 550°C for 10 min can improve the structural properties of the implanted layer and render this surface layer conducting for a whole range of doses. Electron concentrations as high as 10 19 cm -2 have been achieved with these transient annealing techniques.