Modeling of NBTI Kinetics in Replacement Metal Gate Si and SiGe FinFETs-Part-II: AC Stress and Recovery

• Published in: IEEE transactions on electron devices Vol. 65; no. 5; pp. 1707 - 1713
• Main Authors: Parihar, Narendra, Southwick, Richard G., Wang, Miaomiao, Stathis, James H., Mahapatra, Souvik
• Format: Journal Article
• Language: English
• Published: IEEE 01.05.2018
• Subjects: AC-to-dc ratio; bulk-trap generation; duty cycle; FinFET; frequency; hole trapping; interface-trap generation; Kinetic theory; negative-bias temperature instability (NBTI); Predictive models; replacement metal gate high-K metal gate; SiGe channel; Silicon; Silicon germanium; Stress; Stress measurement; Temperature measurement; ultrafast characterization; voltage acceleration factor (VAF)
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2018.2819020

An ultrafast (10-<inline-formula> <tex-math notation="LaTeX">\mu \text{s} </tex-math></inline-formula> delay) measurement technique is used to characterize ac negative-bias temperature instability-induced threshold voltage shift (<inline-formula> <tex-math notation="LaTeX">\Delta \text {V}_\text {T} </tex-math></inline-formula>) in replacement metal-gate-based high-K metal gate Si and SiGe p-FinFETs. Time kinetics of stress and recovery, voltage acceleration factor, temperature activation energy (<inline-formula> <tex-math notation="LaTeX">\text {E}_\text {A} </tex-math></inline-formula>), frequency (f), and pulse duty cycle (PDC) dependence are shown for different germanium percentages (Ge%) in the channel and nitrogen percentages (N%) in the gate insulator. A comprehensive physical model framework based on uncorrelated contributions from interface (<inline-formula> <tex-math notation="LaTeX">\Delta \text {V}_\text {IT} </tex-math></inline-formula>) and bulk oxide (<inline-formula> <tex-math notation="LaTeX">\Delta \text {V}_\text {OT} </tex-math></inline-formula>) trap generation and hole trapping in preexisting defects (<inline-formula> <tex-math notation="LaTeX">\Delta \text {V}_\text {HT} </tex-math></inline-formula>) is used to explain the measured data at different stress biases (<inline-formula> <tex-math notation="LaTeX">\text {V}_\text {GSTR} </tex-math></inline-formula>), temperatures (T), f, and PDCs. Direct-current I-V measurements are used to independently verify the interface-trap generation component for ac stress. End-of-life degradation for different processes under dc and ac conditions is estimated by using the calibrated model and compared to predictions from conventional analytical methods.