Study of segregation behaviour of various dopants in High-Purity Germanium crystal

The advancement of rare-event physics experiments relies heavily on the development of large-volume, high-purity germanium (HPGe) detectors. A key requirement for these detectors is the successful growth of large, single-crystal HPGe with precise control over impurity segregation during the crystal growth process. In this study, we present a detailed investigation of impurity distribution within a single HPGe crystal grown via the Czochralski method in our laboratory. For the first time, we implement high-resolution longitudinal sectioning—approximately 35 distinct segments along the crystal length—to systematically analyze impurity gradients.

We focus on determining the effective segregation coefficients (K_eff) and initial concentrations (C₀) for critical dopants including boron (B), aluminum (Al), gallium (Ga), and phosphorus (P). Hall Effect measurements are used to obtain precise impurity concentration profiles across the entire crystal. The resulting data will provide valuable insight into impurity transport mechanisms and dopant behavior during HPGe growth.

These findings are expected to inform process optimization strategies, improve impurity control, and support the reliable fabrication of large, detector-grade HPGe crystals, thereby contributing to the scalability of future low-background detector technologies.