Formation of hydrogen-related shallow donors in Gei1-xSix crystals implanted with protons

Abstract

If is found that shallow hydrogen-related donors are formed in the proton-implanted dilute Ge1-xSix alloys (0 < x < 0.031) as well as in Si-free Ge samples upon heat-treatments in the temperature range 225-300°C. The maximum concentration of the donors is about 1.5x10^16 cm^-3 for a H+ implantation dose of 1 x10^15 cm^-2. Formation and annihilation temperatures of the protonimplantation-induced donors do not depend on the Si concentration in Ge1-xSix samples. However, the increase in Si content has resulted in a decrease of the concentration of the H-related donors. The possible origin of the H-related donors and mechanisms of Si-induced suppression of their formation are discussed.