Exploring the Impact of Channel Thickness Scaling on PBTI and Low-Frequency Noise in Ultrathin IGZO Transistors
Gan Liu, Qiwen Kong, Xiaolin Wang, Yi-Hsin Tu, Zijie Zheng, Chen Sun, Dong Zhang, Yuye Kang, Kaizhen Han, Gengchiau Liang, Xiao Gong
Abstract
This study presents a thorough investigation into the influence of channel thickness (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t} _{\text {CH}}$ </tex-math></inline-formula>) 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t} _{\text {CH}}$ </tex-math></inline-formula>. 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 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t} _{\text {CH}}$ </tex-math></inline-formula> exhibit heightened susceptibility to electron trapping effects while demonstrating enhanced resilience against hydrogen (H) effects; 2) decreasing <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t} _{\text {CH}}$ </tex-math></inline-formula> values correspond to elevated LFN levels; 3) the mobility fluctuation model (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Delta \mu $ </tex-math></inline-formula>) effectively characterizes LFN behaviors in IGZO FETs, regardless of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t} _{\text {CH}}$ </tex-math></inline-formula> 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.