Speaker
Description
High-purity germanium (HPGe) detectors represent the state of the art in gamma-ray spectroscopy, where position-sensitive capabilities play a crucial role in improving spatial resolution and event reconstruction. The performance of segmented HPGe detectors, however, is still constrained by lithium-diffused n⁺ contacts, which introduce thick inactive layers, limit fine segmentation, and exhibit poor thermal stability during annealing cycles.
A novel technology for the fabrication of thin, thermally stable, and highly segmentable n-type junctions for lithium-free HPGe detectors is presented. The approach combines magnetron sputtering of dopant precursors with Pulsed Laser Melting (PLM), enabling the formation of ultra-shallow junctions with sharp interfaces ideally suited for position-sensitive applications.
The technology has been successfully extended from small-scale devices to large-area, segmented, and thick detectors. Owing to the extremely shallow nature of the junctions, a comprehensive optimization of surface preparation, contamination control, segmentation strategies, and surface passivation has been required.
The resulting detectors exhibit excellent thermal stability under annealing conditions, high inter-segment resistance, and reliable operation at bias voltages exceeding the depletion voltage, ensuring efficient charge collection. These characteristics enable accurate signal localization and support pulse shape analysis techniques.
Overall, PLM-based junctions represent a promising route toward next-generation position-sensitive HPGe detectors, with significant potential impact on nuclear spectroscopy and radiation detection applications.