Evaluation of Si(Li) detectors by a combination of the copper plating method and X-ray analytical microscopy

Copper mapping for copper-plated lithium-ion compensated Si(Li) wafers was performed by a microbeam X-ray fluorescence method. Positional distribution of copper across a cross section of the Si(Li) wafers treated at 120°C for 20 h with no bias applied after complete compensation clearly showed deviation from those that did not undergo the thermal treatment. The surface-barrier detectors fabricated from the thermally treated wafers were found to have better energy resolution both for conversion electrons from ²⁰⁷Bi and for α-particles from ²⁴¹Am. Correlation between the performance of the Si(Li) detectors and the lithium distribution in the intrinsic region was studied on the basis of the experimental results