高k栅介质对短沟道双栅极MOSFET性能的影响∗

摘要

The performance enhancement of MOSFET is slows down, due to the significantly increased gate leakage current that are resulted from the thinner SiO2 thickness in the consistent scaled semiconductor devices. In this work,in order to get a deeper understanding the physical mechanism of how high-k dielectric materials to enhance the MOSFET performance,the effect of high-k dielectric materials and the equivalent oxide thickness (EOT) on the performance of short channel Double Gate MOSFET(DG MOSFET)are investigated by numerical simulation approach that implemented the non-equilibrium Green’s function for-malism. Simulation results show that the channel energy barrier height lowered by increasing the dielectric permittivity and reducing the EOT, which results in the increase of electron density in the channel, so that drain current of MOSFET is the enhanced. In conclusion, the performance of short channel DG MOSFET is enhanced through suppresses the gate leakage current by implemented high-k dielectric materials.%不断缩小半导体器件尺寸将引起二氧化硅绝缘层厚度逐渐地减薄，从而导致从栅极泄漏到衬底的栅极漏电流的明显增加，这制约了MOSFET性能的提升。为了进一步了解采用高k电介质材料增强MOSFET性能的物理机制，本文通过采用基于非平衡格林函数的数值模拟方法，探讨了高k电介质材料及其等效厚度对于短沟道双栅极MOSFET性能的影响。模拟结果表明，高k材料介电常数的增加或等效氧化层厚度（EOT）的减小均将引起沟道区域能量势垒高度的减小，从而导致沟道电子数密度的增加而使漏极电流增加。因此，采用高k电介质材料为绝缘膜可有效地束缚栅极漏电流，从而提高短沟道双栅极MOSFET的性能。