Comparison of NBTI kinetics in RMG Si p-FinFETs featuring Atomic Layer Deposition Tungsten (ALD W) Filling Metal Using B2H6 and SiH4 Precursors

Fast characterization methods are used to study negative bias temperature instability (NBTI) kinetics in replacement metal gate Si p-FinFETs filled by atomic layer deposition (ALD) tungsten (W) using B2H6 or SiH4 precursors. The impact of ALD W filling metal process on threshold voltage shift (Delta V-T), generated interface traps (Delta N-IT), pre-existing hole traps (Delta N-HT), stress bias, and temperature dependence of degradation is analyzed. SiH4-based devices show lower Delta V-T compared to B2H6-based devices under identical stress conditions due to lower Delta N-HT and Delta N-IT. More fluoride-passivated interface traps and higher compressive strain along the channel for ALD W using SiH4 are utilized to explain a lower Delta N-IT than ALD W using B2H6. The time kinetics of NBTI degradation is then modeled for long-term prediction and the maximum overdrive voltage is determined. Devices filled with ALD W using SiH4 show superior reliability and a higher operation overdrive voltage, and can be adopted in the 16/14-nm node CMOS technology and beyond.