Exploring the Impact of Channel Thickness Scaling on PBTI and Low-Frequency Noise in Ultrathin IGZO Transistors

This study presents a thorough investigation into the influence of channel thickness (
${t} _{\text {CH}}$
) on the positive bias temperature instability (PBTI) and low-frequency noise (LFN) characteristics of indium-gallium-zinc-oxide (IGZO) field-effect transistors (FETs) with sub-10-nm
${t} _{\text {CH}}$
. We introduce a novel noise-PBTI-noise (NPN) measurement methodology that integrates LFN and PBTI assessments. Key findings from our analysis include: 1) FETs with reduced
${t} _{\text {CH}}$
exhibit heightened susceptibility to electron trapping effects while demonstrating enhanced resilience against hydrogen (H) effects; 2) decreasing
${t} _{\text {CH}}$
values correspond to elevated LFN levels; 3) the mobility fluctuation model (
$\Delta \mu $
) effectively characterizes LFN behaviors in IGZO FETs, regardless of
${t} _{\text {CH}}$
variations, before and after the PBTI stress conditions; and 4) we identify the passivation effect of the H component generated during PBTI on pre-existing traps. These results underscore the necessity of a comprehensive approach to comprehend and optimize device performance, thereby driving advancements in oxide-semiconductor device technology.