Interface Properties and Surface Leakage of (Hg,Cd)Te Photodiodes.
Abstract
The passivation of Hg(0.8)Cd(0.2)Te photodiode surfaces by an anodic oxide, ZnS, and a bilayer consisting of ZnS covering the anodic oxide was investigated using a combination of electrical and surface spectro-scopic techniques. This approach has allowed us to relate the electrical characteristics of the different passivants with the interface chemistry. The electrical properties of the passivants were revealed by capacitance-voltage measurements of MIS devices and by current-voltage and capacitance-voltage measurements of gate-controlled diodes. X-ray photoelectron spectroscopy together with argon sputtering has provided information both on the chemical species present in the vicinity of the interface and on their chemical states. Our results for the anodic oxide reveal an apparently very non-ideal interface with a substantial Hg depletion in the semiconductor near the interface, yet the density of interface states is quite small (<5 x 10 to the 11th power/sq cm /eV). However, the presence of a large positive charge in the oxide produces an inverted surface in the p-region of the diode which is detrimental to diode operation since it opens up a large channel for surface leakage current.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1981
- Accession Number
- ADA104014
Entities
People
- G. D. Davis
- N. E. Byer
- S. Büchner
- W. Beck
Organizations
- Martin Marietta