Evaluation of implanted InSb p ⁺n diodes passivated with composite anodic oxide/SiO _x stack

This investigation presents detailed characteristics of an im-planted planar InSb p ⁺n diode with a junction area scaled down to 20 × 20 μm ². Low-temperature photo-chemical vapor deposition oxide stacked with an optimized thin anodic film, instead of a gate control structure, is used to control the planar surface potential of the implanted p ⁺n diode under the weak inversion condition on the n-type surface and under weak accumulation on the p-type surface. The zero-bias resistance-area product is 7.6 × 10 ⁴ Ω cm ² at 77 K. To the best of the authors' knowledge, this result represents the best performance of a small-area and implanted planar diode to date. The dark current is controlled by an internal shunt conduction mechanism, which seems to be related to the defects that are produced by the implantation. Low leakage current and high breakdown voltage have proven the feasibility of the composite anodic oxide/SiO _x that is stacked as the passivation structure in small-pixel InSb p ⁺n photodiodes for focal plane array applications.