Scanning Laser Microscopy of Reactive Ion Etching Induced n-Type Conversion in Vacancy-Doped p-Type HgCdTe

Laser-beam-induced-current measurements have been used to characterize the extent of reactive ion etching (RIE) induced type conversion in vacancy-doped p-type Hg0.69Cd0.31Te. The technique allows the spatial extent of RIE induced type conversion to be determined and the donor level concentration profile within the n-type converted region to be estimated, For the RIE processing conditions used (410 mT, CH4/H-2, 0.4 W/cm(2)) and an etch depth of 0.2 mu m, n-type conversion extending similar to 1.5 mu m into the semiconductor was observed. The simple and powerful approach developed in this work is of general application to the study of semiconductor junctions, and can be applied to a range of processing techniques used in the formation of p-n junctions in HgCdTe (e.g., epitaxially grown heterojunctions, ion implantation, ion milling and Hg in-diffusion). (C) 1997 American Institute of Physics.