一种新的Halo掺杂圆柱围栅MOSFET阈值电压解析模型

通过在圆柱坐标系中精确求解泊松方程，建立了全新的Halo掺杂圆柱围栅MOSFET静电势，电场以及阈值电压的解析模型。与采用抛物线电势近似法得到的解析模型相比，当沟道半径远大于氧化层厚度时，新模型更为精确。模型还考虑了Halo区掺杂浓度、氧化层厚度以及沟道半径对器件阈值电压特性的影响。结果表明，采用中等程度的halo区掺杂浓度、较薄的栅氧化层以及较小的沟道半径可以有效改善器件的阈值电压特性。解析模型与三维数值模拟软件ISE所得结果高度吻合。

New analytical threshold voltage model for halo-doped cylindrical surrounding-gate MOSFETs

Using exact solution of two-dimensional Poisson equation in cylindrical coordinates, a new analytical model comprising electrostatic potential, electric field and threshold voltage for halo-doped surrounding-gate MOSFETs is developed. It is found that new analytical model exhibits higher accuracy than that based on parabolic potential approximation when the thickness of silicon channel is much larger than that of the oxide. It is revealed that moderate halo doping concentration, thin gate oxide thickness and small silicon channel radius are needed to improve threshold voltage characteristics. The derived analytical model agrees well with three-dimensional numerical device simulator ISE.