CERIUM OXYFLUORIDE ANTIREFLECTION COATING FOR GROUP II-VI PHOTODETECTORS AND PROCESS FOR FORMING SAME

摘要

A durable quarter wave antireflection coating for a photodetecting device 20, the photodetecting device being formed within a radiation absorbing layer 22 of HgCdTe which is epitaxially grown upon a surface of a substantially transparent Group II-VI substrate 24 having an index of refraction of between approximately 2.2 and 2.8. By example, the substrate 24 may comprise CdZnTe or CdTe. The antireflection coating 26 is formed upon a radiation receiving surface of the substrate 24. The antireflection coating may comprise a layer of CeOxF(3.0-x), where x has a value within the range of approximately zero to approximately 1.0. The CeOxF(3.0-x) layer is formed by an ion beam sputter technique, the CeOxF(3-x) layer being sputtered from a source comprised of CeF3 in the presence of a predetermined pressure of oxygen. In general, the antireflection coating may comprise a fluoride compound formed with a metal of the Lanthanide rare earth series which is substantially transparent to infrared radiation.