Leakage current quenching and lifetime enhancement in 3D pillar structured silicon PIN diodes

摘要

Structures containing three dimensional (3D) pillars, wires and tubes have applications in sensors, photodetectors as well as solar cells. We have been developing a thermal neutron detector by utilizing a 3D pillar architecture where the pillars are constructed out of a PIN diode material, and filling this structure with a neutron sensitive material,¹⁰B [1, 2]. By optimizing the pillar diameter, spacing and height, neutron detection efficiency > 50% is possible [3, 4]. Fig. 1 shows the schematic of a pillar structured detector. However, the large surface-to-volume ratio resulting from the 3D design can result in a high reverse leakage current, which results in a high noise floor for the device, causing a decrease in detector efficiency. Here we report passivation methods to reduce the leakage current by passivating the sidewall surface by wet chemical treatements and oxidation.