Avalanching silicon drift photodetector (A+SDP)

The performance of solid-state photodetectors is limited by noise due to their capacitance and leakage current. A new type of photodetector is being investigated, which contains a micro-avalanche multiplication gain stage incorporated into the small anode structure of a silicon drift photodetector (SDP). This technology is expected to result in improved performance over large area avalanche photodiodes (APD's) because of the very small region of multiplication in the new A+SDP versus multiplication over the entire active area for APD's. APD reliability has generally deteriorated as a function of the size of the devices being manufactured. The A+SDP will be markedly better than PIN diodes because of both the low capacitance and the avalanche multiplication. The device also promises to be better than standard large area Silicon Drift Photodetectors (SDP's) by mitigating the remaining noise due to the leakage current that dominates the performance of these devices at room temperature. Large area SDP's require cooling to well below 0 degree(s)C to obtain satisfactory leakage current-related noise. Physical device simulation tools were used to model the dopant concentrations, E-field magnitude and potential distributions. A+SDP's could have practical application in scintillation detectors for gamma ray spectroscopy as well as PMT replacements in nuclear medicine.© (2001) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.