Implementation of sub-100 nm vertical channel-all-around (CAA) thin-film transistor using thermal atomic layer deposited IGZO channel

Abstract In–Ga–Zn–O (IGZO) channel based thin-film transistors (TFT), which exhibit high on–off current ratio and relatively high mobility, has been widely researched due to its back end of line (BEOL)-compatible potential for the next generation dynamic random access memory (DRAM) application. In this work, thermal atomic layer deposition (TALD) indium gallium zinc oxide (IGZO) technology was explored. It was found that the atomic composition and the physical properties of the IGZO films can be modulated by changing the sub-cycles number during atomic layer deposition (ALD) process. In addition, thin-film transistors (TFTs) with vertical channel-all-around (CAA) structure were realized to explore the influence of different IGZO films as channel layers on the performance of transistors. Our research demonstrates that TALD is crucial for high density integration technology, and the proposed vertical IGZO CAA-TFT provides a feasible path to break through the technical problems for the continuous scale of electronic equipment.