Contactless junction contrast of HgCdTe n-on-p-type structures obtained by reactive ion etching induced p-to-n conversion
Faculty of Computing, Health and Science
School of Engineering and Mathematics
The continuous shrinking of HgCdTe device dimensions in micro- and opto-electronics requires the development of new non-destructive methods able to determine the quality of etching techniques, junction integrity, doping profiles, and the presence of electrically active defects with nanometer resolution. In this paper, we have used a contactless contrast imaging technique to examine junction integrity and recombination activity in n-on-p HgCdTe mid-wave infrared (MWIR) photodiodes. This method allows the direct imaging of junctions, type conversions, dislocation densities, and diffusion profiles as an electromorphological map of the wafer. Experimental and theoretical laser-beam induced current (LBIC) analysis have been used to confirm the results of imaging studies, and to elucidate the effects of the electron beam on the device structure and integrity.