INFLUENCE OF ELECTRON-IRRADIATION ON PHYSICAL-PROPERTIES OF GERMANIUM-DOPED SILICON SINGLE-CRYSTALS

An investigation was made of dislocation-free silicon single crystals which were either doped with germanium (N(Ge) = 10(20) cm-3) or undoped. They exhibited n- or p-type conduction and were grown by the Czochralski method along the <111> direction. The concentration of phosphorus or boron was approximately 10(14) and 10(15) cm-3 in n- and p-type crystals, respectively. These single crystals were irradiated with fast (E = 6 MeV) electrons in doses of D = 5 x 10(12) - 10(17) cm-2 and were then subjected to isochronous annealing for 30 min in the temperature range 200-1000-degrees-C. The process of formation of radiation defects in the germanium-doped single crystals differed from those in the undoped silicon. Introduction of germanium into single-crystal silicon reduced somewhat its radiation sensitivity and tended to restore (after annealing) the minority carrier lifetime in the irradiated material.