Radiation Physics and Chemistry 61 (2001) 743–745 Ways of providing radiation resistance of magnetic field semiconductor sensors I.A. Bolshakova*, S. Krukovskii, R. Holyaka, A. Matkovskii, A. Moroz Magnetic Sensor Laboratory, State Univ ‘‘Lviv Polytechnics’’, 1 Kotliarevsky St., 290013 Lviv, Ukraine Abstract Hall magnetic field sensors resistant to hard ionizing irradiation are being developed for operation under the radiation conditions of space and in charged particle accelerators. Radiation resistance of the sensors is first determined by the properties of semiconductor materials of sensitive elements; we have used microcrystals and thin layers of III–V semiconductors. Applying complex doping by rare-earth elements and isovalent impurities in certain proportions, we have obtained magnetic field sensors resistant to irradiation by fast neutrons and g-quanta. Tests of their radiation resistance were carried out at IBR-2 at the Joint Institute for Nuclear Research (Dubna). When exposed to neutrons with E=0.1–13MeV and intensity of 10 10 ncm @2 s @1 , the main parameter of the sensorsFtheir sensitivity to magnetic fieldsFchanges by no more than 0.1% up to fluences of 10 14 ncm @2 . Further improvement of radiation resistance of sensor materials is expected by means of a combination of metallurgical methods of complex doping with the technology of radiation modification, which includes an interchanging of nuclear doping and fast neutron irradiation with thermoprocessing cycles. A special magnetometric system is to be developed in which the main element is the functionally integrated magnetometric transducer consisting of a semiconductor Hall microgenerator and a copper microsolenoid, which forms the actuating field around the microgenerator. The application of such a magnetometric system with radiation resistant magnetic field sensors will provide magnetic field measurements with an accuracy of 0.1% under hard radiation conditions. r 2001 Elsevier Science Ltd. All rights reserved. Keywords: Hall generator; Radiation resistance; Magnetic measuring system 1. Introduction Growing demands are being placed on improving the operating parameters of magnetic field sensors for measurement, accuracy being the foremost. Operation under radiation conditions is one of the problems in developing semiconductor materials with improved radiation resistance while preserving sensitivity. Our present method of complex metallurgical doping of III–V semiconductor microcrystals and thin films by donor (Sn,Te), rare-earth (Yb,Gd) and isovalent impurities (Al,Bi,Sb) allows us to obtain magnetic sensors in which radiation resistance is improved by more than a factor of 10 when compared with existing ones. The method is based on mechanisms that provide minimum oxygen content in the materials, also stimulat- ing drains for primary radiation defects. It is known that oxygen interacts actively with primary radiation defects under irradiation, forming deep acceptor level com- plexes (Guillot, 1988). Majority carriers are bound with the complexes, and this results in change of material parameters and sensor sensitivities. Rare-earth elements actively getter the oxygen (Masterov, 1990) and avoid forming complexes. Also, an elastic stress field is formed in the crystal lattice since the covalent radius for these RE elements differ from those of crystal matrix atoms. A similar effect is caused by isovalent impurities which support the formation of overlapped elastic stress fields of the separate atoms of an impurity, in this way *Corresponding author. Tel./fax: +380-322-970393. E-mail address: inessa@mail.lviv.ua (I.A. Bolshakova). 0969-806X/01/$-see front matter r 2001 Elsevier Science Ltd. All rights reserved. PII:S0969-806X(01)00393-0