摘要
量子力学效应对于深亚微米 MOSFET特性的影响随着衬底浓度的增加和栅氧层厚度的减小而日益显著 .实验结果表明 :量子力学效应能够导致开启电压明显的漂移 .本文通过比较薛定谔方程在抛物线势垒下的数值解和三角势垒下的解析解验证了 MOS结构弱反型区量子力学效应三角势垒近似的正确性 .在计算弱反型区量化层内子带结构的基础上 ,提出量子化有效态密度和经典有效态密度的概念 ,分析了载流子在子带中的分布情况 ,讨论了量子力学效应影响开启电压的两个因素 ,并在此基础上给出了开启电压的量子力学修正模型 .该模型准确地揭示了量子力学效应影响开启电压的物理实质 。
With increasing of the substrate dopant concentration and decreasing of the gate oxide thickness,the influence of Quantum Mechanical Effects (QME) on deep\|submicron MOSFET characteristics are getting more and more significant.Experiments results show that QME can result in noticeable threshold voltage ( V th ) shift. In this paper, numerical solution with parabolic potential well and analytical solution with triangular well are compared, and the validity of triangular well approximation is demonstrated. Based on the calculation of the subband structure in the quantized region in weak inversion regime, the concepts of Quantum Effective State Density and Classical Effective State Density are proposed, the carrier distribution in subbands is analyzed and the two factors that influence the V th shift are discussed. Finally, a quantum correction model to threshold voltage is given, which reveals the physical nature of the influence of QME on the V th shift and gives consistent results with experiments.
