Auger Compositional Depth Profiling of the Metal Contact-TlBr Interface

摘要

Degradation of room temperature operation of TlBr radiation detectors with time is thought to be due to electromigration of Tl and Br vacancies within the crystal as well as the metal contacts migrating into the TlBr crystal itself due to electrochemical reactions at the metal/TlBr interface. Scanning Auger electron spectroscopy (AES) in combination with sputter depth profiling was used to investigate the metal contact surface/interfacial structure on TlBr devices. Device-grade TlBr was polished and subjected to a 32% HCl etch to remove surface damage and create a TlBr_(1-x)Cl_x surface layer prior to metal contact deposition. Auger compositional depth profiling results reveal non-equilibrium interfacial diffusion after device operation in both air and N_2 at ambient temperature. These results improve our understanding of contact/device degradation versus operating environment for further enhancing radiation detector performance.