Low-Energy Charged-Particle Detection via an Avalanche Silicon Detector coupled to an Amorphous Silicon Active Layer

This SBIR Phase I project will develop a solid-state sensor with on-chip amplification to deliver low-energy (< 10 keV/e-) particle-detection with similar sensitivity and timing performance as existing vacuum-tube multiplication instruments, but do so at low-bias, low-cost, and in a compact, ruggedized package. The work will complete the prototype development of a silicon-based detector scheme for electrons, protons, and heavy ions with a thin-film (4 – 1000 nm) amorphous silicon front active layer and an integrated silicon avalanche layer for on-chip amplification. The amorphous silicon creates charge-pairs for even the lowest of energies, and the p+/n silicon detector produces multiplication gain at low voltage (< 100 V). Compared with channel electron multipliers or microchannel plates that operate at ~1 kV, this not only reduces the power requirements, but it eliminates the arcing risks that can accompany compact instrument and spacecraft designs. The detector: (a) eliminates the need for the ultra-high vacuum required for the vacuum tube technologies, (b) tolerates dust via its solid-state design, and (c) can deliver charged-particle flux measurements with CMOS integration. The Phase I work will establish the simplest design that allows low-energy particle detection by evaluating: (a) thinned silicon avalanche diodes operating at ~50 V, (b) amorphous silicon thin-film diodes operating at 0 V, and (c) a combined device that marries the amorphous silicon sensing layer with the multiplying silicon back layer.