Towards a laser beam induced current test structure for the nondestructive determination of junction depth in HgCdTe photodiodes

Correct placement of the p-n junction depth of diodes in HgCdTe infrared focal plane arrays is critical for ensuring the highest performance of diodes in the array. To date, most methods of determining the junction depth in HgCdTe have been destructive, based around wet chemical etching of the sample until the n-region has disappeared. In this paper we present some introductory work on the application of laser beam induced current, a non-destructive characterisation technique, to a specially designed junction depth test structure. The test structure has small geometric dimensions, which enables the peak magnitude of the LBIC signal to be sensitive to variations in the depth of the p-n junction.