Department of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST) , 373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Republic of Korea.
ACS Appl Mater Interfaces. 2014 Mar 12;6(5):3150-5. doi: 10.1021/am403971x. Epub 2014 Feb 28.
In this study, germanium nanowire junctionless (GeNW-JL) metal-oxide-semiconductor-field-effect-transistors (MOSFETs) exhibited enhanced electrical performance with low source/drain (S/D) contact resistance under the influence of Ar plasma treatment on the contact regions. We found that the transformation of the surface oxide states by Ar plasma treatment affected the S/D contact resistance. With Ar plasma treatment, the germanium dioxide on the GeNW surface was effectively removed and increased oxygen vacancies were formed in the suboxide on the GeNW, whose germanium-enrichment surface was obtained to form a germanide contact at low temperature. After a rapid thermal annealing process, Ni-germanide contacts were formed on the Ar-plasma-treated GeNW surface. Ni-germanide contact resistance was improved by more than an order of magnitude compared to that of the other devices without Ni-germanide contact. Moreover, the peak field effect mobility value of the GeNW-JL MOSFETs was dramatically improved from 15 cm(2)/(V s) to 550 cm(2)/(V s), and the Ion/off ratio was enhanced from 1 × 10 to 3 × 10(3) due to Ar plasma treatment. The Ar plasma treatment process is essential for forming uniform Ni-germanide-contacts with reduced time and low temperature. It is also crucial for increasing mass productivity and lowering the thermal budget without sacrificing the performance of GeNW-JL MOSFETs.
在这项研究中，锗纳米线无结（GeNW-JL）金属-氧化物-半导体场效应晶体管（MOSFET）在接触区域的氩等离子体处理的影响下，表现出增强的电性能和较低的源/漏（S/D）接触电阻。我们发现，氩等离子体处理对表面氧化物状态的转变影响了 S/D 接触电阻。通过氩等离子体处理，GeNW 表面上的二氧化锗被有效地去除，并且在 GeNW 的次氧化物中形成了更多的氧空位，其富锗表面形成了低温下的金属化接触。经过快速热退火处理，在氩等离子体处理的 GeNW 表面上形成了 Ni 锗化物接触。与没有 Ni 锗化物接触的其他器件相比，Ni 锗化物接触电阻提高了一个数量级以上。此外，由于氩等离子体处理，GeNW-JL MOSFET 的峰值场效应迁移率值从 15 cm(2)/(V s)显著提高到 550 cm(2)/(V s)，Ion/off 比从 1 × 10 提高到 3 × 10(3)。氩等离子体处理过程对于形成具有减少时间和低温的均匀 Ni 锗化物接触是必不可少的。它对于提高产量和降低热预算而不牺牲 GeNW-JL MOSFET 的性能也是至关重要的。
