Detectivity Optimization of InGaAs Photon Emission Microscope Systems

Although photon emission microscope (PEM) systems are widely used in integrated circuit failure analysis, there is no known quantitative baseline to assess and compare the overall sensitivity performance of PEM systems. This paper describes a method to quantify the overall sensitivity of PEM systems based on spectral detectivity measurements. It has been applied to HgCdTe (MCT) and InGaAs PEM systems. It is also applied to an InGaAs PEM system to quantify the change in the detectivity of the InGaAs PEM system as the temperature of the detector changes. The method is also used to compare the signal to noise ratio of an emission image by normal time integration with digital integration where many frames of an emission image is added up to produce a single emission image