RAPID THERMAL ANNEALING OF SELENIUM IMPLANTED InP

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.