Abstract
Silicon drift detectors (SDDs) are used in high-resolution and high-count-rate X-ray spectroscopy. SDDs have application in high-energy physics for particle tracking and in astronomy for telescopes. SDD with high-resolution and low leakage, require optimized device design. This thesis presents a study of circular (cylindrical) SDD, for X-ray spectroscopy using TCAD simulations. Influence of different biasing schemes and device geometry are presented. Device design is optimized on three performance metrics - low leakage current, low anode capacitance and high radial drift field. Capacitance variation due to fringe effects is studied. Limitations on biasing voltages due to punch through are explored. To evaluate uniformity and strength of drift field, concepts of drift channel and mean drift field along the drift channel are introduced which qualify the performance of device. Different surface potential profiles are evaluated considering mean drift field and uniformity as criteria. Finally, large area cylindrical SDD of thickness 1000 µm and radius 5000 µm is presented with leakage current limited to bulk generation current (100 nA), capacitance less than 100 fF and mean drift field of 600 V/cm.