PREPARATION OF SILICON FOR HIGH VOLTAGE POWER DEVICES USING MAGNETIC FIELDS AND NEUTRON TRANSMUTATION

CZOCHRALSKI SILICON (CZ) WITH HIGH RESISTIVITY AND IMPROVED DOPANT HOMOGENEITY CAN BE GROWN USING MAGNETIC FIELD DURING CRYSTAL GROWTH AND NEUTRON TRANSMUTATION DOPING (NTD). IN THIS WORK, THE PROCESSING AND CHARACTERIZATION OF 100 MM NTD-MAGNETIC CZOCHRALSKI (MCZ) SI IS PROPOSED FOR HIGH VOLTAGE SEMICONDUCTOR POWER DEVICES (6000 VOLTS). DEVICE AND MATERIAL EVALUATION INCLUDING CRYSTAL GROWTH, NTD, THERMAL ANNEALING, RESISTIVITY UNIFORMITY, LIFE-TIME AND DEVICE CHARACTERISTICS WILL BE INVESTIGATED. EFFECT OF MAGNETIC FIELD AND CRUCIBLE ON IMPURITY CONCENTRATION AND UNIFORMITY OF HIGH RESISTIVITY SI WILL BE EXAMINED WITH EMPHASIS ON STUDIES OF OXYGEN IMPURITIES, PRECIPITATION OF OXYGEN AND FORMATION OF DONOR IMPURITIES ASSOCIATED WITH IT,AS WELL AS ELECTRICALLY ACTIVE IMPURITIES E.G. C, B AND A1. PROCESSING OF 2000 AMPS THYRISTORS AND RECTIFIERS WITH BLOCKING VOLTAGES OF 6000 VOLTS WILL BE USED AS THE FINAL AND ULTIMATE TEST OF MATERIAL EVALUATION.