Search

Metal oxide-based resistive random access memory devices are highly attractive candidates for next-generation nonvolatile memories, but the resistive switching phenomena remain poorly understood. This article focuses on the microscopic understanding of the initial forming step, which is decisive for the switching process. The integrated resistive switching memory effect in Ti / Hf O 2 / TiWN metal insulator metal structures is studied. After forming, transmission electron microscopy investigations pointed out the presence of a funnel-shaped region, in the ON state of the cell, where slightly oxidized Ti (Ti Ox ) was present within Hf O 2 dielectric. Modeling of the measured ON state conductance of the cell with the semi-classical approximation is consistent with a conductive nanometric Ti Ox filament (or a sum of sub-nanometric Ti Ox filaments) present in the funnel-shaped region. The conductive area is likely formed by diffusion after the dielectric breakdown. [ABSTRACT FROM AUTHOR]

The properties of WN[SUBx]C[SUBy] films deposited by atomic layer deposition (ALD) using WF[SUB6], NH[SUB3], and triethyl boron as source gases were characterized as a diffusion barrier for copper metallization. It is noted that the as-deposited film shows an extremely low resistivity of about 350 μΩ cm with a film density of 15.37 g/cm[SUP3]. The film composition measured from Rutherford backscattering spectrometry shows W, C, and N of ∼ 48, 32, and 20 at. %, respectively. Transmission electron microscopy analyses show that the as-deposited film is composed of face-centered-cubic phase with a lattice parameter similar to both β-WC[SUB1-x] and β-W[SUB2]N with an equiaxed microstructure. The barrier property of this ALD-WN[SUBx]C[SUBy] film at a nominal thickness of 12 nm deposited between Cu and Si fails only after annealing at 700 °C for 30 min. [ABSTRACT FROM AUTHOR]