Utilization of wet chemical etching for revealing defects in GaAs x-ray detector arrays

The aim of the study was to check the potential of wet chemical etching to improve the performance of GaAs-based X-ray detector arrays in view of their applications in medical diagnostics and nondestructive evaluation. The paper presents results of tests provided on SI GaAs detector arrays of different pixel sizes. The characterization of detector parameters was performed by current-voltage measurements and electron microscopy. The effect of MESA etching on the electrical device properties of reverse breakdown voltage and current density increases with decreasing pixel size. Irregular subsurface leakage current paths between individual pixels have been revealed by defect-selective shallow etching.