Se-Man Oh

Superior bipolar resistive switching behaviors of solution-processed HfAlOx thin film for nonvolatile memory applications

We report on the bipolar resistive switching behavior and uniform cumulative distribution of set/reset voltage observed from the resistive random access memory (ReRAM) device based on a solution-processed HfAlOx thin film. The HfAlOx thin film was spin-coated from a mixture of HfOx and AlOx solutions at ratio. The dominant conduction mechanism of a solution-processed HfAlOx thin film is found to be the ohmic behavior in the low-resistance state (LRS) and high-resistance state (HRS) in the low-voltage region, whereas the Poole–Frenkel emission is dominant in the HRS in the high-voltage region. Outstanding reliability in terms of endurance and retention characteristics was achieved. The solution-processed HfAlOx thin film can be a promising candidate for the application in ReRAM devices with glass or flexible substrates.

Tunneling Properties in High-k Insulators with Engineered Tunnel Barrier for Nonvolatile Memory

The metal-insulator-silicon (MIS) capacitors with and high-k dielectrics (, ) were fabricated, and the current-voltage characteristics were investigated. Especially, an effective barrier height between metal gate and dielectric was extracted by using Fowler-Nordheim (FN) plot and Direct Tunneling (DT) plot of quantum mechanical(QM) modeling. The calculated barrier heights of thermal , ALD , and are 3.35 eV, 0.6 eV, 1.75 eV, and 2.65 eV, respectively. Therefore, the performance of non-volatile memory devices can be improved by using engineered tunnel barrier which is considered effective barrier height of high-k materials.

Degradation of electrical characteristics in Bio-FET devices by O 2 plasma surface treatment and improving by heat treatment

The effects of surface treatment by plasma on the Bio-FETs were investigated by using the pseudo-MOSFETs on the SOI substrates. After a surface treatment by plasma with different RF powers, the current-voltage and field effect mobility of pseudo-MOSFETs were measured by applying back gate bias. The subthreshold characteristics of pseudo-MOSFETs were significantly degraded with increase of RF power. Additionally, a forming gas anneal process in 2 % diluted ambient was developed to recover the plasma process induced surface damages. A considerable improvement of the subthreshold characteristics was achieved by the forming gas anneal. Therefore, it is concluded that the pseudo-MOSFETs are a powerful tool for monitoring the surface treatment of Bio-FETs and the forming gas anneal process is effective for improving the electrical characteristics of Bio-FETs.