Simulation of the SiGe use effi-ciency for the production of high-voltage thyristors

Abstract

Power semiconductor devices often subjected to appreciable terrestrial atmospheric neutron flows. For the improvement of their radiation hardness, the use of silicon doped with Ge (SiGe) was proposed. The stability of last is much higher in comparison with convenient type silicon. Earlier received results confirmed effectiveness of isovalent doping of silicon with germanium at radiation tests of low power (current approx. 100 mA) discrete devices. Power thyristors Т122-25 are used for the transformation and regulation of AC and DC current up to 25А, frequency up to 500 Гц in the circuits with voltage 100 – 1600V (1-16 class). In the data sheets directly indicated that these devices are not suitable for operating in the conditions of ionizing radiation. Therefore, the main practically important mission of the article was the confirmation the technological efficiency of SiGe use, or, in other words, possibility of radiation hard material use for high voltage power devices technology. The purpose of the present work was the modeling of the experimental findings for the informed choice of Ge concentration for manufacturing of high voltage thyristors Т122. The data concern the workable general-purpose power thyristors Т122 type yield, manufactured in accordance with the identical technology, based on CZ-Si и CZ-Si. At SiGe implementation in the technology of power semiconductors was observed no monotonic change of the thyristors gain share for devices of high (10, 11, 12) ranges (classes), the value of pulse recurring voltage in off-state is 1000, 1100 and 1200 V. Simulation of the experimental results was performed in MathCAD. The concentration of Ge, suitable for the manufacture of high-voltage thyristors, is in the range 2 ·1019 - 1·1020 cm-3, i.e. in the linear region of dependence. Previously, the authors have experimentally shown the possibility and mechanism of increasing the radiation resistance of SiGe with a concentration of Ge 5·1019 cm-3. It is allowed to admit the possibility of reaching the radiation resistance of high-voltage power discrete thyristors when tested with γ-quanta in the dose range up to ≅ 3·106 mSv.