New PIN diode structure for neutron dose measurement

Planar silicon PIN diodes have been proposed as neutron dosimeters before. In this paper, a new structure of planar silicon PIN diode with ring shaped backside n + doping is proposed. Simulation shows effective improvement in the current distribution compared with a normal planar PIN structure. Diodes with different lateral spaces between p + and n + , i.e., 200–500 μm, were fabricated. The sensitivity of the diodes to neutron irradiation was measured. The dependence of the sensitivity on the working current of the diode was analyzed. The impact of the lateral space on the diode sensitivity was investigated. The results show that the sensitivity of the diode is proportional to the square root of the current at high-level injection and increases with the lateral space between the p + and n + regions.