SIMS Analysis of Impurity in HgCdTe Epilayers of Infrared Focal Plane Array

摘要

Infrared Focal Plane Array (IRFPA) is a critical component for advanced infrared systems. It plays an important role in different applications including environmental monitoring, biomedicine, process control, science and space. To get high performance IRFPA detectors, quality of HgCdTe epilayers is a critical concern. In this paper, we focus on the impurity in HgCdTe epilayers, which is closely related to the leakage current performance of IRFPA chip. Firstly, the principle and characteristics of the Secondary Ion Mass Spectrometry (SIMS) are introduced. The high sensitivity and all-elements detection ability make it an effective technology to study trace impurity. Secondly, the impurity elements and their distribution properties in HgCdTe epilayers are investigated by SIMS technology. Impurities of Li, Na, K and Ca are found in epilayers. Finally, the source of the impurity is analysised based on the epitaxial growth process of HgCdTe epilayers. The impact of the impurity on device performance is also discussed.