Conformal Passivation of High Aspect Ratio HgCdTe Surfaces by ALD Using a Novel Cd-Precursor

"HgCdTe is the material of choice for high performance infrared red focal plane arrays (IRFPA) used in militarys night vision systems. One of the major problems IRFPA manufacturers face is the ineffective passivation of the highly reticulated HgCdTe detector surfaces, which results in poor performance. Furthermore, newly evolved FPA technology requires the creation of much challenging high-aspect-ratio geometries. Thus, equally important to the passivation development is the conformal coating technology on high-aspect-ratio surfaces. Thus, the goal of the proposed program is to develop new precursors and perform well-defined ALD passivation on HgCdTe focal plane arrays. The novel metalorganic precursors that were developed in the Phase I demonstrate physical and chemical properties consistent with the requirements of atomic layer deposition at low temperature. The proposed passivation material and technique using highly conformal atomic layer deposition (ALD) will allow the DOD to develop high-performance infrared focal plane array detectors with complex morphologies that can operate under wider operating conditions, using lower-cost processes. To ensure ideal device performance, the passivation technology will be optimized to yield uniform, conformal, pinhole-free and stoichiometric composition processed at low substrate temperatures, which will provide robust electrical and physical barrier properties. "