Tungsten nanocrystal memory devices improved by supercritical fluid treatment

Abstract

A supercritical CO2 (SCCO2) fluid technique is proposed to improve electrical characteristics for W nanocrystal nonvolatile memory devices, since the thickness and quality of tunnel oxide are critical issues for the fabrication of nonvolatile memory devices. After SCCO2 treatments, C-V curves are restored to normal, as well as the leakage current of W nanocrystal memory devices are reduced significantly. It reveals that W nanocrystal memory devices could be formed with shorter oxidation time, moreover, dangling bonds and trapping states initially created within an incomplete oxidized film will be efficiently repaired after SCCO2 treatment.

Electrical Properties of the Thin Films Using a Low Temperature Supercritical Carbon Dioxide Fluid Process

“…8, these results reveled that the H 2 O molecules were operatively react in dangling bonds and traps of the SCCO 2 treated thin films after SCF treatment. The strong O 1s bonding of the as-deposited thin film after SCF treatment was observed [16]- [25]. Fig.…”

Charge-Trapping Non-Volatile Memories

“…On the other hand, after NH 3 plasma treatment, the traps in the surrounding dielectric could be passivated and therefore lateral migration of the stored carriers between NCs by trap-assistance tunneling could be reduced and consequently the charge retention was improved ). Despite the H 2 -annealing and plasma treatment, a supercritical CO 2 fluid technique having advantage of low thermal budget can also been applied to passivate traps in the dielectric to reduce leakage (Chen and Black 2007). According to ) the NC surface is a highly curved surface and therefore the Si lattice at surface is highly strained in comparison with the plane surface.…”

Nonvolatile Memory Characteristics of WSi2 Nanocrystals Embedded in SiO2 Dielectrics

“…[12][13][14] Especially, WSi 2 has a large work function of 4.8 eV, good chemical stability with the Si atom, and compatibility with the current semiconductor industry process due to its good thermal stability. [15][16][17] For these reasons, NFGM devices with WSi 2 nanocrystals are expected to exhibit good electrical performance and a smaller metal-diffusion problem compared to metallic nanocrystals because of their good thermal stability.…”