Investigation of new chemistries for processing and passivation of III-V antimonide based infrared detectors

In the pursuit of lower cost and higher performance infrared detectors, antimonide-based materials have been increasingly investigated over the past decade. One of the greatest advantages of the III-V materials system is the potential for improved uniformity stemming from the incorporation of lattice-matched wide bandgap, unipolar barrier devices (i.e. “nBn”). However, with the increasing demand for larger-format, smaller-pitch focal plane arrays (FPA) new processing and passivation techniques have become necessary. This is especially true for FPAs that require fully reticulated detector pixel structures to meet modulation transfer function (MTF) requirements. This paper will discuss our investigation of several mesa delineation strategies to improve consistency, reduce surface current, and maximize optical fill factor in antimonide based dual-band infrared photodetectors. The resulting etch profiles, surface chemistry and photoresist etch selectivity for new inductively coupled plasma etch chemistries and conditions will be discussed.