Influence of Impurity Complexes on the Electrophysical Properties of Germanium

Abstract—Samples of n-type germanium (doped with three different impurities) with and without an oxygen impurity have been studied. To reveal the interaction of oxygen in n-Ge crystals with As, Sb, and Bi impurities, the effect of transverse magnetoresistance (very sensitive to the presence of complexes in the crystal) was chosen as a research method. It was shown that, in the germanium samples doped with antimony and bismuth, low-temperature annealing leads to the formation of electrically active impurity complexes that affect both the magnitude and the form of the dependence of the transverse magnetoresistance Δρ⊥/ρ0 on the magnetic field strength H. The insensitivity of the oxygen-enriched germanium crystals with an arsenic impurity (in contrast to the accompanying impurities of antimony and bismuth) to low-temperature thermal annealing has been revealed. This fact is of not only scientific but also practical interest since such annealing is in many cases one of the inalienable technological operations in the creation of a wide class of semiconductor devices, and the absence of oxygen in germanium (used for those purposes) is not always guaranteed by the supplying companies. It was shown that the use of impurity with a large tetrahedral radius in n-Ge crystals (at a practically equal concentration of charge carriers) is accompanied not only by a decrease in the tensoresistance ρX/ρ0 in the saturation region but also by a decrease in the rate of an increase in ρX/ρ0 with increasing pressure. The latter circumstance finds its manifestation in a decrease in the slope of the curves ρX/ρ0 = f (X).