Approach to Low Contact Resistance Formation on Buried Interface in Oxide Thin-Film Transistors: Utilization of Palladium-Mediated Hydrogen Pathway

Abstract

Amorphous oxide semiconductors (AOSs) with low off-currents and processing temperatures offer promising alternative materials for next-generation high-density memory devices. The complex vertical stacking process of memory devices significantly increases the probability of encountering internal contact issues. Conventional surface treatment methods developed for planar devices necessitate efficient approaches to eliminate contact issues at deep internal interfaces in the nanoscale complex structures of AOS devices. In this work, we report the pioneering use of palladium thin film as a high-efficiency active hydrogen transfer pathway from the outside to the internal contact interface via low-temperature postannealing in the H 2 atmosphere, and the formation of highly conductive metallic interlayer effectively solves the contact issues at the deeply buried interfaces in devices. The application of this method reduced the contact resistance of Pd electrodes/amorphous indium−gallium−zinc oxide (a-IGZO) thin-film by 2 orders of magnitude, and thereby the mobility of thin-film transistor was increased from 3.2 cm 2 V −1 s −1 to nearly 20 cm 2 V −1 s −1 , preserving an excellent bias stress stability. This technology has wide applicability for the solution of contact resistance issues in oxide semiconductor devices with complex architectures.

Wide process temperature of atomic layer deposition for In2O3 thin-film transistors using novel indium precursor (N,N′-di-tert butylacetimidamido)dimethyllindium

“…This enhancement is due to the suppression of disorder-induced subgap states through lattice ordering and the increased carrier density arising from shallow donors in the polycrystalline In 2 O 3 films, leading to higher Hall mobility [8,9,30]. Specifically, we suspect that the subtle differences in drain current observed between 5 and 10 µm channel lengths are due to the effective channel length phenomenon induced by thermal processes [31][32][33][34].…”