Passivation of mercury cadmium telluride surfaces

The practical aspects of HgCdTe surface passivation, as related to devices and applications, are reviewed. Currently used technologies are classified in two categories: thick deposited dielectrics and a two‐layer combination of a thin native film with a thick deposited dielectric film. The first category includes ZnS, low‐temperature photochemical vapor deposited SiO₂ (photox), and electron cyclotron resonance plasma deposited SiN_x. The second category includes anodic oxide, plasma oxide, photochemical native oxide, anodic sulfide, and anodic fluorides. The unique behavior of HgCdTe surfaces, metal‐insulator semicoductor structures, and gate‐controlled p–n junctions are reviewed. The surface requirements of HgCdTe devices of interest for present and next‐generation focal plane arrays are discussed in terms of the reviewed technologies.