In this paper we introduce a new HgCdTe 2-dimensional numerical simulator, HanYang University Semiconductor Device Simulator (HYSEDES). HYSEDES adopts the modifield transport models to describe the inherent natures of HgCdTe such as the degeneracy, the nonparabolic conduction band, and the band offset at heterointerface. It also takes into account various generation - recombination mechanisms regarding tunnelling phenomena and optical generation. For the advanced devices employing multiple junctions, all the material parameters are described as a function of the position. The simulation results are reported for photovoltaic devices and focal plane array. We also proposed a structure to improve the characteristics in focal plane array, i. e., to reduce crosstalk with slight degrading quantum efficiency.
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In the conventional simulations for HgCdTe device, the empirical mobility model is used which lacks in generality. Especially, the field dependent mobility is found to be wrong by comparing Monte Carlo results. The semi - empirical electron mobility model for the simulator is proposed in this paper. Low field mobility consists of two terms related to ionised impurity and phonon scattering. It is calculated by using the relaxation time approximation, which gives the information on the dominant factors affecting the mobility. The ionised impurity mobility model is modified based on Brooks - Herring model to include the degeneracy effect and overlap integral. For field dependent mobility, a new formula is proposed to take into account features of the dominant scattering mechanism such as nonparabolic relation between energy and wave function at high field. Final formula is accomplished by introducting fitting parameters extracted from Monte Carlo simulation results. This new model retains more physical meaning than conventional model.
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