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 x 1012 and 1 x 1015 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 55 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 Si3N4 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 x 1012 cm-2, implant gave an electrical activity of 17%. Activities of about 35% were obtained for doses of about 5 x 1014 cm-2 using either the graphite strip heater or the e-beam. These layers had peak electron concentrations in excess of 1 x 1019 cm-3. We have also found that the Si3N4 deposition process at 550°C for 10 minutes can improve the structural properties of the implanted layer and render this surface layer conducting for a whole range of doses.
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