Random Dopant Fluctuation-Induced Threshold Voltage Variation-Immune Ge FinFET With Metal-Interlayer-Semiconductor Source/Drain

• Published in: IEEE transactions on electron devices 2016-11, Vol.63 (11), p.4167-4172
• Main Authors: Shin, Changho, Kim, Jeong-Kyu, Kim, Gwang-Sik, Lee, Hyunjae, Shin, Changhwan, Kim, Jong-Kook, Cho, Byung Jin, Yu, Hyun-Yong
• Format: Article
• Language: English
• Subjects: CMOS; Doping; FinFET; FinFETs; germanium; II-VI semiconductor materials; interlayer; random dopant fluctuation (RDF); Resource description framework; Semiconductor process modeling; Threshold voltage; threshold voltage variation; Zinc oxide; Zinc oxides
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2016.2606511

The impact of process-induced random dopant fluctuation (RDF)-induced threshold voltage (Vth) variation on the performance of 7-nm n-type germanium (Ge) FinFETs with and without a metal-interlayer-semiconductor (MIS) source/drain (S/D) structure is investigated using 3-D TCAD simulations. In order to reduce the RDF-induced V th variation, an MIS S/D structure with a heavily doped n-type zinc oxide (ZnO) interlayer is used in the S/D region of the Ge FinFET. Thus, without performance degradation, the Ge FinFET with an MIS S/D structure achieves approximately threefold reduction in the RDF-induced V th variation (versus without an MIS S/D structure). The impact of various fin parameters (i.e., fin height and fin width) on the RDF-induced V th variation is also investigated. It is noteworthy that variation is suppressed as the fin height (fin width) increases (decreases).