金属/界面层/n型锗结构中的固定电荷和界面偶极子对其接触电阻的调制效果和机理的研究

Ge has received great attentions as a rather potential channel material for 10 nm technology node CMOSFET and beyond, due to its intrinsic high electron and hole nobilities. For the implementation of Ge channel in CMOSFET, one major challenge is to obtain sufficiently low contact resistance for n type Ge (n-Ge). One promising solution about this challenge is to employ metal/insulator/n-Ge structure. For this structure the fixed charges and interfacial dipole are found to play a very important role on the contact resistance. However, the reported publications do not decouple and clarify the fixed bulk charges in the insulator, fixed interfacial charges at the interface and the interfacial dipoles, as well as their impacts on the contact resistance. The solution of the above problem is beneficial to understanding the effects of each of the above three parameters. As a result, this project investigates the effects of the fixed bulk charges, fixed interfacial charges and interfacial dipole in the metal/insulator/n-Ge structure on the contact resistance, aiming at the following key scientific problems: (1) to decouple and clarify the fixed bulk charges in the insulator, fixed interfacial charges at the interface and the interfacial dipoles, as well as their impacts on the contact resistance; (2) to investigate the physical origins of the fixed bulk charges in the insulator, fixed interfacial charges at the interface and the interfacial dipoles; (3) to clarify the physical mechanism of modulation of contact resistance by these three parameters. This project can provide technical route for n-Ge contact resistance.

随着集成电路工艺进入10纳米及以下技术节点，传统硅衬底遇到很大的挑战，锗衬底由于其较高的电子和空穴迁移率成为研究的热点。在锗衬底的研究中，一个主要挑战是实现n型锗的低的接触电阻。金属/界面层/n型锗结构展现出巨大的解决问题潜力和应用前景。此结构中影响接触电阻的非常重要的物理因素是固定电荷和界面偶极子。但是当前的研究报道并没有严格区分固定体电荷和界面电荷以及界面偶极子的调制效果，而是混淆和笼统的讨论这三者对接触电阻的影响，缺乏系统而深入的研究。上述问题的解决有助于理解和改善器件性能。鉴于上述问题，本课题研究金属/界面层/n型锗结构中的电荷和界面偶极子对于n型锗接触电阻的调制，立足于关键共性科学问题：体电荷和界面电荷、以及界面偶极子的严格区分和定量表征、物理起源、以及其对接触电阻的调制效果和机理。本课题的开展对进一步调制n型锗接触电阻具有重要的指导意义，为器件性能的改善提供理论指导和技术路线。

随着集成电路工艺进入10纳米及以下技术节点，传统硅衬底遇到很大的挑战，锗衬底由于其较高的电子和空穴迁移率成为研究的热点。在锗衬底的研究中，一个主要挑战是实现n型锗的低的接触电阻。金属/界面层/n型锗结构展现出巨大的解决问题潜力和应用前景。此结构中影响接触电阻的非常重要的物理因素是固定电荷和界面偶极子。但是当前的研究报道并没有严格区分固定体电荷和界面电荷以及界面偶极子的调制效果，而是混淆和笼统的讨论这三者对接触电阻的影响，缺乏系统而深入的研究。上述问题的解决有助于理解和改善器件性能。鉴于上述问题，本课题研究金属/界面层/n型锗结构中的电荷和界面偶极子对于n型锗接触电阻的调制，立足于关键共性科学问题：体电荷和界面电荷、以及界面偶极子的严格区分和定量表征、物理起源、以及其对接触电阻的调制效果和机理。本课题实验表征了金属/界面层/n型锗结构中的电荷和界面偶极子量级在0.2eV，能够有效肖特基势垒高度，并发现通过退火条件的改变，能够有效改善偶极子量级达0.5eV。本课题的开展对进一步调制n型锗接触电阻具有重要的指导意义，为器件性能的改善提供理论指导和技术路线。