Low temperature (< 150? Text Color) annealed amorphous indium-gallium-tin oxide (IGTO) thin-film for flash memory application

Abstract

This study first attempted to fabricate and study the properties of flash memory devices using amorphous In-Ga-sn-O (IGTO) material as a channel material. Compared with devices using amorphous In-Ga-Zn-O (IGZO) ma-terial as a channel material, amorphous IGTO flash memory devi ces exhibit improved memory characteristics with faster write/erase speeds (10 mu s), improved program/erase (P/E) efficiency, lower sub-threshold swing (SS), higher field effect mobility (mu FE) and enhanced on-current to off-current ratio (ION/IOFF). The erasing method and possible mechanism to enhance erasing efficiency utilizing light-assisted negative gate biasing were discussed in this paper. The photo transition is closely related to oxygen vacancy, therefore, the light-assisted approach photo -ionizing oxygen vacancies to generate holes could be a way to achieve erasing under the negative gate bias. Compared with amorphous IGZO thin film, amorphous IGTO thin film has a lower electron affinity and more oxygen vacancies that can provide more holes. In the P/E characterization under different circumstances, amorphous IGTO devices had a wider memory window (MW), and longer retention behaviors. These properties broaden the applications of modern flash device circuits and serve as a reference for future advances in flash storage technology.