Effect of germanium single crystals annealing on the behavior of oxygen impurity

Production of semiconductor Germanium contributes to the development of aerospace instrumentation. Dislocation-free Germanium single crystals are used for making effective space-based solar cells. The crystals with extremely low concentration of impurities and defects are used for the manufacturing of digital devices in distributed power systems of the onboard space equipment. Oxygen is one of the main impurities in Germanium, which impairs the properties of crystals and leads to formation of dislocations. The present research has been aimed at analyzing the effect of Germanium single crystal annealing on the behavior of oxygen impurity. Oxygen-dissolved in Germanium has been characterized using Fourier transformed infrared spectrometry. The oxygen concentration in crystals was determined based on optical density from the absorption band at 843 cm-1. It is established that oxygen dissolved concentration in Germanium is variable from 0,2·1016 to 1,3·1016 сm-3 depending on their quality. The effect of Germanium single crystals annealing on the behavior of oxygen impurity has been studied in the temperature range of 350-450 °C. It was found that oxygen concentration and form of its presence varies under the influence of annealing. It was established that oxygen band maximum shifts from 843 to 856 cm-1 when its concentration increases under the influence of annealing in the atmosphere with 1≤ ≤ 103 Pa. The annealing at lower leads to decrease in the oxygen band intensity of the 843 cm-1 due to the formation of thermal-donors on the basis of interstitial dissolved oxygen. These results can be used in the semiconductor Germanium technology to obtain single crystals with necessary oxygen content and form of its presence, thus, with therefore, controlled due to the properties.