对称双栅高斯掺杂应变Si金属氧化物半导体场效应管的二维解析模型

Two-dimensional analytical models for double-gate(DG) strained-Si metal-oxide-semiconductor field transistor with vertical gaussian doping profile

基于扩散、阈值调整和离子注入等工艺过程导致器件的沟道区的掺杂分布不均匀,提出对称双栅高斯掺杂应变硅MOSFET器件,并对其相关特性进行研究。通过对沟道二维泊松方程求解建立该器件结构的表面势和阈值电压模型,分析弛豫SiGe层的Ge组分和掺杂偏差σn对表面势和阈值电压的影响。此外,还对比分析高斯掺杂对称双栅应变硅MOSFET器件和均匀掺杂对称双栅应变硅MOSFET器件的表面势和阈值电压。研究结果表明:阈值电压随应变Si膜中Ge组分的增加而降低;表面势和阈值电压随偏差σn的增加而减小;高斯掺杂对称双栅应变硅MOSFET器件和均匀掺杂对称双栅应变硅MOSFET器件的表面势和阈值电压相差较大,表明非均匀掺杂对器件表面势和阈值电压等影响较大。

Considering that diffusion, threshold voltage adjustment and ion implantation process cause the device channel doping distribution to be uneven, a symmetrical double-gate strained-Si metal-oxide-semiconductor field transistor（MOSFET） with a vertical Gaussian doping profile was proposed, and the two-dimensional surface potential model and threshold voltage model for this MOSFET were studied to solve Poisson’s equation. The effects of Gaussian doping straggle parameter σn on surface potential and threshold voltage were investigated. The influence of Ge fraction in the relaxed layer on the surface potential and threshold voltage models was analyzed. Both models of DG MOSFET with Gaussian doping and uniform doping were compared, respectively. SCEs（short-channel effect） and（Drain-Induced-Barrier-lowering） DIBL were analyzed. The results show that the doping distribution has great influence on the device such as surface potential and threshold voltage.