Geometrical and Structural Design Schemes for Trench-Shaped Vertical Channel Transistors Using Atomic-Layer Deposited In-Ga-Zn-O

Abstract

Trench-structured In-Ga-Zn-O vertical thin-film transistors (T-VTFT) was fabricated with a channel length of 400 nm. T-VTFTs showed channel width-dependent field-effect mobility owing to the back-channel scattering, and the mobility of 24.1 cm2 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$/$ </tex-math></inline-formula> Vs was finally obtained with a channel width of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1 ~\mu \text{m}$ </tex-math></inline-formula> . Alternatively, the asymmetric operations of conventional mesa-shaped VTFTs were improved in a symmetrical way owing to the structural benefits of the T-VTFT, leading to excellent immunity against the drain-induced barrier lowering.