A new two-dimensional （2D） analytical model for the threshold-voltage of fully depleted SOI MOSFETs is derived. The 2D potential distribution functions in the active layer of the devices are obtained through solving the 2D Poisson＇s equation. The minimum of the potential at the oxide-Si layer interface is used to monitor the threshold voltage of the SOI MOSFETs. This model is verified by its excellent agreement with MEDICI simulation using SOI MOSFETs with different gate lengths,gate oxide thicknesses,silicon film thicknesses,and channel doping concentrations.
We improve the genetic algorithm by combining it with a simulated annealing algorithm. The improved algorithm is used to extract model parameters of SOI MOSFETs, which are fabricated with standard 1.2μm CMOS/SOI technology developed by the Institute of Microelectronics of the Chinese Academy of Sciences. The simulation results using this model are in excellent agreement with experimental results. The precision is improved noticeably compared to commercial software. This method requires neither a deeper understanding of SOl MOSFETs model nor more complex computations than conventional algorithms used by commercial software. Comprehensive verification shows that this model is applicable to a very large range of device sizes.
