Comparative study on NBTI kinetics in Si p-FinFETs with B2H6-based and SiH4-based atomic layer deposition tungsten (ALD W) filling metal. (April 2020)

• Record Type: Journal Article
• Authors: Zhou, Longda; Wang, Guilei; Yin, Xiaogen; Ji, Zhigang; Liu, Qianqian; Xu, Hao; Yang, Hong; Simoen, Eddy; Wang, Xiaolei; Ma, Xueli; Li, Yongliang; Kong, Zhenzhen; Jiang, Haojie; Luo, Ying; Yin, Huaxiang; Zhao, Chao; Wang, Wenwu
• Is Part Of: Microelectronics and reliability. Volume 107(2020)
• Publication Date: 2020-04
• Subjects: ALD W filling metal -- Fluorine -- Strain -- NBTI -- P-FinFETs -- High-k and metal gate (HKMG); Electronic apparatus and appliances -- Reliability -- Periodicals; Miniature electronic equipment -- Periodicals; Appareils électroniques -- Fiabilité -- Périodiques; Équipement électronique miniaturisé -- Périodiques; Electronic apparatus and appliances -- Reliability; Miniature electronic equipment; Periodicals; 621.3815
• DOI: 10.1016/j.microrel.2020.113627
• Languages: English
• ISSNs: 0026-2714

Abstract

Abstract: A comparative study on negative bias temperature instability (NBTI) is carried out in replacement metal gate Si p-FinFETs featuring atomic layer deposition (ALD) tungsten (W) filling metal using B2 H6 and SiH4 precursors. A fast measurement technique is used to characterize the threshold voltage shift (ΔVT ). The effect of ALD W filling metal process on ΔVT, generated interface traps (ΔNIT ), pre-existing hole traps (ΔNHT ), stress voltage, and temperature dependence of degradation is demonstrated. Comparing with their B2 H6 -based counterpart, SiH4 -based devices show reduced ΔVT under identical stress conditions due to reduced ΔNHT and ΔNIT . SiH4 -based devices exhibit a 1.5 times higher fluorine content at the interfaces and larger compressive strain in the channel than B2 H6 -based devices, which are found to be responsible for the reduced ΔNIT . A modeling framework is proposed to model the long-term time evolution of NBTI degradation, and the predicted maximum overdrive voltage is compared. SiH4 -based devices exhibit superior reliability and a 20% improvement in the maximum operation overdrive voltage than B2 H6 -based devices, and can be implemented in the advanced CMOS technology. Highlights: NBTI kinetics of two p-FinFETs have been compared with B2H6 and SiH4-based ALD W filling metal by fast measurement methods. SiH4 -based devices exhibit reduced NBTI degradation and a 20% improved lifetime than B2 H6 -based devices. SiH4 -based devices show a 1.5 times higher fluorine content at the interface than B2 H6 -based devices. SiH4 -based devices exhibit a larger compressive channel strain than B2 H6 -based devices. The enhanced fluorine content and channel strain result in reduced trap generation in SiH4 -based devices.