Investigation Of Electrical Crosstalk In InGaAs Focal Plane Array

Infrared detectors made of lattice matched In Ga As materials are particularly used in defense, and in industrial system because they are relatively economical, respond rapidly to light amplitude modulation, and high reliability. In recent years, with the development of growth and preparation of materials, the requirements of In Ga As focal plane array(FPA) performance in all areas become more and more high. Crosstalk characteristic is closely correlated to higher sensitivity and higher resolution imaging of focal plane array(FPA). This makes the study of the crosstalk of In Ga As focal plane arrays gradually attracted by people.In the former half of this thesis, the theoretical formulas and models used in the simulation were introduced systematically, including Poisson’s equation, carrier continuity equations, transport equations and generation-recombination models. Then, in order to verify the reliability of the models, we showed the simulation results of In Ga As focal plane array internal quantum efficiency and response. When we confirm the models were right, the changing of dark current depend on the detector structures, the thickness and doping concentration of absorbing layer were analyzed. The thicknesses of depletion area of p-i junction and n-i junction and the electric potential distribution in In0.53Ga0.47As/In P PIN detector were calculated quantitatively. It is demonstrated that dark current of planar structure is less than the mesa structure’s. When the absorption layer thickness is less than 1.5mm, the dark current increases with the absorption layer thickness increasing, and when the absorption layer thickness is greater than 1.5mm, the dark current will tend to balance, no longer changes. When the doping in the absorption layer is low, the dark current decreases with the absorption layer thickness increasing. The ability of seize bias and the depletion layer width of p-i junction in In0.53Ga0.47As/In P PIN detector were better than n-i junction, so n-i junction was always be ignored when we analyzing the device.In the latter half of this thesis, the electrical crosstalk of typical planar and mesa In0.53Ga0.47As/In P FPAs as a function of: illumination wavelength, incidence, as well as the etching depth in the mesa structures were investigated quantitatively in detail by simulation. It is demonstrated that mesa structures possess better electrical crosstalk characteristics compared to the planar designs. Significantly, the crosstalk is lower for shorter wavelength radiation and the front-side illumination devices show better electrical crosstalk characteristics than do the back-side illuminated devices, which are ascribed to the influence of material absorption depth and the p-i junction depletion width of such structures. It is also found that the electrical crosstalk appears to be greatly suppressed when the etching depth of the mesa structure is completed through the entire absorption layer of the device. The results suggest design rules for In Ga As FPA with low electrical crosstalk. In addition to the above content, we also simulated the Vis-SWIR In Ga As detector’s quantum efficiency and two experiment of measuring In Ga As FPA crosstalk. The simulated quantum efficiency of Vis-SWIR In Ga As detector and the result of the first experiment of measuring In Ga As FPA crosstalk were consistent with the experiment results. But the odd phenomenon in the second experiment didn’t appear in our simulation, in the preliminary analysis, we think it is because we didn’t consider the optical crosstalk.