Channel shape and interpoly dielectric material effects on electrical characteristics of floating-gate-type three-dimensional fin channel flash memories

Abstract

Floating-gate (FG)-type three-dimensional (3D) fin channel flash memories with triangular fin (TF) and rectangular fin (RF) channels and different interpoly dielectric (IPD) materials have been successfully fabricated using (100)- and (110)-oriented silicon-on-insulator (SOI) wafers and orientation-dependent wet etching. The electrical characteristics of the fabricated FG-type 3D fin channel flash memories including threshold voltage (Vt) variability, program/erase (P/E) speed, memory window, endurance, and data retention at room temperature and 85 °C have been comparatively investigated. A higher P/E speed, a larger memory window, and a lower-voltage operation are experimentally obtained in the TF channel flash memories with an Al2O3–nitride–oxide (ANO) IPD layer (TF-ANO) than in the RF channel ones with the same ANO IPD layer (RF-ANO) and the TF channel ones with an oxide–nitride–oxide (ONO) IPD layer (TF-ONO). The larger memory window and lower-voltage operation of TF-ANO flash memories are due to the high-k effect of the Al2O3 layer and the electric field enhancement at the sharp foot edges of the TF channels. It was also found that data retention for all fabricated FG-type 3D fin channel flash memories shows a weak dependence on temperature.

Plasma-Assisted ALD of Highly Conductive HfNx: On the Effect of Energetic Ions on Film Microstructure

“…Conductive transition metal nitride (TMN) films find many applications in nano-electronics. They are used as metal electrodes in metal oxide semiconductor field effect transistors (MOSFETs) [1][2][3][4], and as diffusion barriers in inter-connects [5][6][7][8]. In view of the continuous scaling of semiconductor devices, the application of TMN films at small dimensions requires ultra-thin films with low resistivity, besides forming stable interfaces, e.g.…”

“…In view of the continuous scaling of semiconductor devices, the application of TMN films at small dimensions requires ultra-thin films with low resistivity, besides forming stable interfaces, e.g. with the underlying high-k HfO 2 [1,3,4,8]. Specifically, thin films of titanium nitride and tantalum nitride tend to form undesirable oxy-nitrides at the interface with HfO 2 [4,8].…”

(Invited) Floating Gate Type SOI-FinFET Flash Memories with Different Channel Shapes and Interpoly Dielectric Materials

“…As a further study, in this work, we fabricated scaled FG-type SOI-FinFET flash memories with different fin channel shapes and IPD materials, and compared their electrical characteristics including V t variability, P/E speed, memory window, endurance, and data retention at different temperatures (32).…”

Fabrication and Characterization of p-Channel Charge Trapping Type FOI-FinFET Memory with MAHAS Structure

“…Thus, the scaled planar NOR-type flash memories with gate length (L g ) smaller than 100 nm are very difficult to fabricate. [1][2][3][4] On the other hand, three-dimensional (3D) channel devices, such as fin field-effect transistors (FinFET) or fin-channel tri-gate (TG) device provide excellent SCE immunity thanks to the strong electrostatic controllability of the multiple gates. 5 Moreover, threshold voltage (V th ) variability in the FinFET or TG devices is much smaller than that in the conventional bulk planar MOSFETs because V th variation induced by the random dopant fluctuation (RDF) is negligible in FinFET or TG devices owing to the undoped fin-channels.…”