TiN Thickness Impact on BTI Performance

In this letter, we investigate the effects of the TiN metal-gate (MG) electrode on bias temperature instability (BTI) in high-
$k$
/MG metal–oxide–semiconductor field-effect transistors. Experimental data show that a thicker TiN film effectively improves bias temperature stability. The thick TiN layer prevents oxygen diffusion toward the
$\alpha$
-Si gate electrode; therefore, it suppresses the number of oxygen vacancies in the LaO/HfSiON gate dielectric stack, lessens BTI degradation, and improves interface quality.