Development of photodetectors for image converters: Doping of silicon with selenium from the gas phase

Abstract

High-speed recording of processes in the IR spectral range can be carried out using image converters of the “semiconductor photodetector + gas discharge gap” type. To develop photodetectors with the properties required for this purpose, the effect of the selenium vapor pressure P Se on the doping efficiency of single-crystal silicon with selenium has been studied. Selenium was introduced by diffusion in sealed quartz cells at a temperature of 1240°C in the pressure range P Se = 0.27–1.0 atm. Doped samples were studied by performing temperature measurements of the Hall effect. A heavy dependence of the concentration of the impurity centers introduced on P Se was observed. It was found that the doping effect is the same for starting crystals produced by floating zone melting and by the Czochralski method. The data obtained were used to fabricate photodetectors that can be employed in high-speed thermography with the use of the image converters under consideration.