Abstract
Solid-state thermal neutron detectors are desired to replace He-3 tube tube-based technology for the detection of special nuclear materials. He-3 tubes have some issues with stability, sensitivity to microphonics and very recently, a shortage of He-3. There are numerous solid-state approaches being investigated that utilize various architectures and material combinations. Our approach is based on the combination of high-aspect-ratio silicon PIN pillars, which are 2 mu m wide with a 2 mu m separation, arranged in a square matrix, and surrounded by B-10, the neutron converter material. To date, our highest efficiency is similar to 20 % for a pillar height of 26 mu m. An efficiency of greater than 50 % is predicted for our device, while maintaining high gamma rejection and low power operation once adequate device scaling is carried out. Estimated required pillar height to meet this goal is similar to 50 mu m. The fabrication challenges related to B-10 deposition and etching as well as planarization of the three-dimensional structure is discussed.