Neeraj Shenoy

EECS Department, University of California, Berkeley

Technical Report No. UCB/EECS-2023-175

May 12, 2023

http://www2.eecs.berkeley.edu/Pubs/TechRpts/2023/EECS-2023-175.pdf

<p>Bias temperature instability (BTI) has become an increasingly pressing degradation mechanism due to its impact on the reliability of metal-oxide-semiconductor field-effect transistors (MOSFETs). BTI results in a gradual shift of MOSFET characteristics, such as threshold voltage (V_T), over time. We are interested in the reliability of p-type silicon-on-insulator (SOI) MOSFETs (L_g = 90 nm) incorporating a 1.8 nm HfO₂-ZrO₂ superlattice (HZH) gate stack. This gate stack exhibits an effective oxide thickness of 7.5 &#8491 due to negative capacitance (NC) effects. In this paper, we estimate the end-of-life (EOL) degradation of threshold voltage (&#916V_T) of low EOT NC p-SOI MOSFETs using a negative bias temperature instability (NBTI) physical model. The model is created based on experimental data of stress time (t_STR) and &#916V_T of p-SOI MOSFETs under constant temperature (T = 85&#8451) and varying overdrive voltage (V_OV) conditions. We find &#916V_IT, the interface trap contribution, is the major contributor to the overall &#916V_T, while &#916V_HT and &#916V_OT, the hole trapping and bulk trap generation contributions, are negligible. So, we extrapolate the &#916V_IT physical model out to t_STR = 10 years &#8776 3 * 10⁸ seconds and find estimates for degradation of &#916V_T at EOL. We now have a better sense of the reliability of NC p-SOI MOSFETs under constant T and varying V_OV conditions.</p>

Advisors: Jeffrey Bokor

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BibTeX citation:

@mastersthesis{Shenoy:EECS-2023-175,
    Author= {Shenoy, Neeraj},
    Editor= {Salahuddin, Sayeef},
    Title= {Modeling EOL Degradation for NBTI Reliability of Low EOT Negative Capacitance p-SOI MOSFETs},
    School= {EECS Department, University of California, Berkeley},
    Year= {2023},
    Month= {May},
    Url= {http://www2.eecs.berkeley.edu/Pubs/TechRpts/2023/EECS-2023-175.html},
    Number= {UCB/EECS-2023-175},
    Abstract= {<p>Bias temperature instability (BTI) has become an increasingly pressing degradation mechanism due to its impact on the reliability of metal-oxide-semiconductor field-effect transistors (MOSFETs).  BTI results in a gradual shift of MOSFET characteristics, such as threshold voltage (V<sub>T</sub>), over time.  We are interested in the reliability of p-type silicon-on-insulator (SOI) MOSFETs (L<sub>g</sub> = 90 nm) incorporating a 1.8 nm HfO<sub>2</sub>-ZrO<sub>2</sub> superlattice (HZH) gate stack.  This gate stack exhibits an effective oxide thickness of 7.5 &#8491 due to negative capacitance (NC) effects.  In this paper, we estimate the end-of-life (EOL) degradation of threshold voltage (&#916V<sub>T</sub>) of low EOT NC p-SOI MOSFETs using a negative bias temperature instability (NBTI) physical model. The model is created based on experimental data of stress time (t<sub>STR</sub>) and &#916V<sub>T</sub> of p-SOI MOSFETs under constant temperature (T = 85&#8451) and varying overdrive voltage (V<sub>OV</sub>) conditions.  We find &#916V<sub>IT</sub>, the interface trap contribution, is the major contributor to the overall &#916V<sub>T</sub>, while &#916V<sub>HT</sub> and &#916V<sub>OT</sub>, the hole trapping and bulk trap generation contributions, are negligible.  So, we extrapolate the &#916V<sub>IT</sub> physical model out to t<sub>STR</sub> = 10 years &#8776 3 * 10<sup>8</sup> seconds and find estimates for degradation of &#916V<sub>T</sub> at EOL.  We now have a better sense of the reliability of NC p-SOI MOSFETs under constant T and varying V<sub>OV</sub> conditions.</p>},
}

EndNote citation:

%0 Thesis
%A Shenoy, Neeraj 
%E Salahuddin, Sayeef 
%T Modeling EOL Degradation for NBTI Reliability of Low EOT Negative Capacitance p-SOI MOSFETs
%I EECS Department, University of California, Berkeley
%D 2023
%8 May 12
%@ UCB/EECS-2023-175
%U http://www2.eecs.berkeley.edu/Pubs/TechRpts/2023/EECS-2023-175.html
%F Shenoy:EECS-2023-175