METHOD FOR NEUTRON-TRANSMUTATION DOPING OF SILICON Russian patent published in 2002 - IPC

FIELD: electronic and electrical engineering; industrial nuclear doping of semiconductor materials in fast reactors for manufacturing semiconductor devices. SUBSTANCE: method includes irradiation of container holding silicon ingots in nuclear reactor channel with pulsating neutron flux delivered at definite time intervals between pulses (so-called dose-and-time schedule) with known original and varying with time distribution of neutron flux density through ingot height and check-up of neutron fluence averaged lengthwise of ingots in container using for the purpose neutron chamber and vertical assemblies of forward-charge incremental current sensors installed in reactor measuring channels. Vertical assemblies of current sensors are placed in opposing measuring channels with their vertical offset through half the distance between these sensors in assembly. Electric signal picked off ionization chamber and current sensors is entered in computer whose software provides for correction of current-sensor readings basing on ionization chamber readings. Computer output is coupled with automatic-control facilities that function to move container and hold it within uniform irradiation area basing on present readings of current sensors and setting value of dose-and-time schedule; as soon as desired integral silicon radiation dose is attained, container is brought out of irradiation channel. Curve used to estimate distribution function of neutron flux at interval between two adjacent readings of sensor sections displayed in computer are given in description of invention. Proposed method for producing single-crystalline silicon doped with phosphor in nuclear reactor enhances quality of radiation-doped silicon to any desired resistivity ratings, that is reduces spread in resistivity values, and provides for producing silicon of desired electrophysical characteristics and for retaining single-crystalline structure of ingot. EFFECT: enhanced yield of semiconductor devices with improved characteristics. 2 cl, 1 dwg, 1 ex