Conception and Manufacturing of Four Diodes for Tritium Detection

Abstract

Tritium dosimetry constitutes a major nuclear safety issue for fusion reactors. Among the numerous tritium detection techniques, beta-voltaic detection is a simple and real-time approach, consisting in using a diode to collect the beta particles resulting from tritium decay and convert it in an electrical signal. Particularly, the use of a wide bandgap semiconductor, such as silicon carbide (4 H-SiC), for the diode conception, allows to increase its electrical conversion efficiency. In this context, we have designed four different SiC-based diode structures to perform tritium beta-voltaic detection: two PIN diodes, a Metal-Insulator-Semiconductor (MIS) diode, and a Junction Barrier Schottky (JBS) diode. From Monte-Carlo and finite elements simulations, we have optimized, for each diode, several structural parameters in order to maximize the electrical response, such as p + layer thickness and doping concentration, distance between ohmic contacts, n- doping concentration. The four optimized diodes have then been manufactured in cleanroom, and are now ready for experimental tests.