This paper reviews the development and present status of mid-wavelength infrared (MWIR) HgCdTe photodiode technology in Australia. MWIR n-on-p photodiodes have been produced by both mercury in-diffusion and by boron ion-implantation on Hg-vacancy doped p-type HgCdTe. The photodiodes are planar structures passivated with thermally evaporated ZnS. High performance MWIR photodiodes have been developed with R_oA product of 2 X 10⁶ (Omega) cm² at 77 K. Recent work has focused on developing novel passivation processes based on anodic sulphurdization in which thermally evaporated ZnS is subsequently anodized in a non-aqueous sodium sulphide solution. Preliminary results suggest that this improves the insulating properties of thermally evaporated ZnS layers. The leakage currents, as measured through a 1 mm² MIS structure at a 1 V bias at 77 K, for the anodized ZnS layer are in the sub-picoamp range for all devices fabricated, whereas for the non-anodized layer the leakage currents are typically much larger by up to 3 - 4 orders of magnitude.

Date Published: 8 September 1995
PDF: 12 pages
Proc. SPIE 2552, Infrared Technology XXI, (8 September 1995); doi: 10.1117/12.218210

Published in SPIE Proceedings Vol. 2552:
Infrared Technology XXI
Bjorn F. Andresen; Marija Strojnik, Editor(s)