Line profile of built-in field distribution of lithium drifted silicon detectors observed by using SEM

The microstructure of the built-in-field distribution of a lithium-drifted silicon detector was investigated using a scanning electron microscope (SEM). It was found that lithium ions diffuse into the region adjacent to the lithium-diffused layer, resulting in an overcompensation of lithium ions in the region expected to be become intrinsic. Effects of the overcompensation on the characteristics of the detector are discussed. It was shown that the pn junction is at the outermost edge of the remarkable difference in donor density at the interface of the original lithium-diffused layer and the lithium-drifted layer