Reliability Impacts of Tapered Nanosheets and Localized Layout Effects in MBCFETs Fabricated with 2NM Logic Technology Featuring GAA

In this paper, we report on the reliability impacts of tapered-nanosheets (NSs) and metal-gate-boundary (MGB) localized layout effects (LLE) in Multi-Bridge-Channel field effect transistors (MBCFETs) fabricated using 2nm gate-allaround (GAA) logic technology. We subjected T-shaped, dumbbell-shaped (D-shape), and stair-shaped (S-shape) structures to bias temperature instability (BTI) tests. Unique transitions in tapered NSs alter the source/drain (SD) volume, leading to stress changes in the channel. N-type transistors (SGN) positive BTI (PBTI) threshold voltage (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}}}$</tex>) shifts are primarily influenced by initial threshold voltage (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}0}}$</tex>), while P-type transistors (SGP) negative BTI (NBTI) <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}}}$</tex> shifts are affected by both of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}0}}$</tex> and stress induced hole trap barrier changes. Additionally, SGP NBTI <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}}}$</tex> shifts exhibit different behaviors depending on the width ratio. The BTI behavior in fall-type and rise-type S-shaped structures is similar to that in T-shaped and D-shaped structures. BTI <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}}}$</tex> shifts by MGB distance are influenced by oxygen vacancy exchange-induced <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}0}}$</tex> shifts. Furthermore, BTI <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}}}$</tex> shifts due to neighboring <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">${{\mathrm{V}}_{\mathrm{t}}}$</tex> options are modified by dipole formation.