Transparent multi-level-cell nonvolatile memory with dual-gate amorphous indium-gallium-zinc oxide thin-film transistors

Abstract

A fully transparent, nonvolatile charge-trap-flash memory that is based on amorphous indium-gallium-zinc-oxide thin film transistors was fabricated with a dual gate (DG) structure for a multi-level-cell (MLC) application. A large memory window was obtained at a low program voltage in the DG read-operation mode owing to the capacitive-coupling effect between the front gate and the back gate. The MLC was implemented by using the DG read-operation mode with four highly stable levels, as follows: A large threshold-voltage difference >3.5 V per level was obtained under a low program voltage <14 V with a fast program speed of 1 ms. In contrast, the conventional single gate operation mode was incompatible with the MLC application.

Nonvolatile memory devices based on undoped and Hf- and NaF-doped ZnO thin film transistors with Ag nanowires inserted between ZnO and gate insulator interface

“…[2][3][4] Various materials such as ferroelectric materials, nano-oating gate dielectrics, and polymer electrets have been proposed to generate memory effect in TFT devices. [5][6][7] Among them, the nano-oating gate dielectric process is considered promising for high performance memory devices. In these device structures a oating gate is used to store and release charge with the memory state represented by a shi in the threshold voltage.…”

Nonvolatile Multistates Memories for High-Density Data Storage

“…38−42 Another effort is to extend memory window based on amorphous In−Ga−Zn−O thin-film transistors 43,44 with a dual-gate cell. 45 Hybrid SSDs that consist of single bit cells and multistates cells have been proposed to provide a trade-off between density and reliability. 46,47 Furthermore, some efforts have demonstrated that NMSM based on the charge effect can be extended to a carbon nanotube, 48 nanocrystals, 49,50 nanowires, 51 two-dimensional materials, 52−55 and organic materials.…”

“…In the respect of materials, high-K gate dielectric beyond HfO 2 is highly desired to improve the reliability and scalability. Besides, data stored in discrete charge trapping sites were reported in silicon nitride − or metal nanoparticles. − Another effort is to extend memory window based on amorphous In–Ga–Zn–O thin-film transistors , with a dual-gate cell . Hybrid SSDs that consist of single bit cells and multistates cells have been proposed to provide a trade-off between density and reliability. , Furthermore, some efforts have demonstrated that NMSM based on the charge effect can be extended to a carbon nanotube, nanocrystals, , nanowires, two-dimensional materials, − and organic materials. − …”

High-Performance Non-Volatile InGaZnO Based Flash Memory Device Embedded with a Monolayer Au Nanoparticles

“…For typical NVM devices, the programming/erasing properties depend on the applied voltage to the control gate electrode (V program /V erase ) that leads to validate the memory window with the corresponding variation in the current level of a device as ‘on’ state and ‘off’ state, describing programmable and erasable constitutes of memories [ 7 , 8 , 9 ]. In this regard, floating gate NVM devices based on various semiconductors, such as two-dimensional (2D) materials (molybdenum disulfide (MoS 2 ) and tungsten disulfide (WS 2 )), [ 3 , 8 , 10 , 11 , 12 , 13 ] oxide materials (indium gallium zinc oxide (IGZO) and zinc oxide (ZnO)) [ 9 , 14 , 15 , 16 , 17 , 18 , 19 , 20 ] and organic materials (pentacene, poly(3-hexylthiophene) (P3HT), and dinaphthothienothiophene (DNTT)) [ 21 , 22 , 23 , 24 , 25 , 26 ] have recently been studied, exhibiting high-performance memory operations with greater endurance and retention properties but are still limited at obtaining reliable reproducibility, larger memory window with on-off ratio, low-temperature processing, and easy fabrication methods.…”