METHOD FOR DETEMINING CONCENTRATIONS OF ALLOYING ADDITIVES IN SEMICONDUCTORS AFTER NEUTRON- TRANSMUTATION ALLOYING Russian patent published in 2003 - IPC

FIELD: radiation technique, namely neutron-transmutation alloying of semiconductors, possibly determination of concentrations of alloying additive (of stable daughter isotope) formed after irradiating semiconductor material by thermal neutrons in nuclear reactor with successive radioactive decay of parent isotope followed with gamma-quantum emitting, particularly for neutron-transmutation alloyed silicon. SUBSTANCE: method comprises steps of irradiating ingots of semiconductor material with neutrons at simultaneously irradiating reference samples with neutrons and keeping them before measurement; determining concentration of alloying additive in irradiated ingots by registering mean counting rate of peak of total capture of gamma-quanta of parent isotope by gamma- spectrometry of reference samples and calculating concentration according to formula: where n - concentration of alloying additive, 1/cub.cm; λ - constant value of parent isotope decay, 1/c; S - mean counting rate at total capture peak of gamma-quanta of parent isotope registered during measurement period, 1/c; t1, t2, t3 - time duration of irradiation, keeping and measurement respectively, c; ε - absolute registration effectiveness of detector of geometry of measured reference sample, percentage units; η - yield of gammaquanta of parent isotope for one decay action, percentage units; V - volume of reference sample, cub.cm; preliminarily calibrating gamma-spectrometer according to registration effectiveness by means of reference radionuclide sources; keeping reference samples of semiconductor material before measuring mean counting rate for 20 - 25 hours from time moment of irradiation termination; after measuring and lowering their induced activity to level of natural radiation background again using them at further irradiation stage. EFFECT: improved safety of process, lowered number of technological operations, reduced labor consumption of measuring process, high accuracy of controlling concentration of one or several alloying additives of semiconductor material at neutron-transmutation alloying. 2 cl, 4 tbl, 2 dwg, 2 ex