کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1822442 | 1526342 | 2015 | 8 صفحه PDF | دانلود رایگان |
The electronic noise of the front-end preamplifier can potentially limit the energy and position resolutions of radiation sensors, a detrimental effect that can be diminished by the use of on-chip amplification. The implementation of an avalanching structure upon a direct-conversion semiconductor-based radiation detector is modeled and demonstrated using high-resistivity silicon. The avalanche particle sensor configuration is designed analytically, and we validated the design with numerical process and device simulations. Process and device simulation results from the sensors modeled with various geometries, doping profile arrangements, and fabrication conditions are reported. We tested the refined numerical design by fabricating and testing diagnostic sensors. Multiplication junctions, based on a junction termination extension design, were created from micrometer-scale highly-doped layers on silicon wafers using both diffusion and ion implantation techniques. For <100 keV energy depositions, our modeling has shown that a gain of ~8 is ideal if one is attempting to optimize the SNR, which is realized in the experimental detectors at an excess bias of 3 V. At that voltage, the energy resolution for 81 keV gamma-rays can, in principle, be reduced from 2.12% to 0.96% (for a kα=0.2 device), the degree of improvement limited by the leakage current of the devices, and within a factor of 2 of the ultimate Fano limit (0.53%).
Journal: Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment - Volume 784, 1 June 2015, Pages 135–142