Silicon-based microstructured semiconductor neutron detectors

Microstructured semiconductor neutron detectors (MSNDs) are semiconductor diodes with deep patterns etched into the substrate. These patterns are backfilled with neutron reactive materials, usually either 6LiF or 10B. Neutron reactions with the reactive material spontaneously cause fission and release charged-particle reaction products that may enter the detector material, thereby producing a measurable electronic signal. Modeling analysis and process implementation reveals certain device optimization features that produce improved results. These important features include the effects of conformal diffusion layers, oxide trapped charge, feature shapes and dimension, choice of backfill materials, and backfill density. The detectors generally operate with a bias of only a few volts, are compact, rugged, and can deliver between 35% to 69% detection efficiency. MSNDs can be operated with common electronics, or they can be commercially obtained with miniaturized compact electronics in a single package. Due to their compact size and low power properties, MSNDs have been used on spacecraft, inserted into wearable detector gear, fashioned into handheld active Bonner style detectors, packaged into moderated hardware, and a variety of other configurations. The theory and operation of MSNDs will be presented, along with some discussion on various configurations and applications of these unique detectors.