RESUMEN
To scale down semiconductor devices to a size less than the design rule of 10 nm, lithography using a carbon polymer hard-mask was applied, e.g., spin-on-carbon (SOC) film. Spin coating of the SOC film produces a high surface topography induced by pattern density, requiring chemical-mechanical planarization (CMP) for removing such high surface topography. To achieve a relatively high polishing rate of the SOC film surface, the CMP principally requires a carbon-carbon (C-C) bond breakage on the SOC film surface. A new design of CMP slurry evidently accomplished C-C bond breakage via transformation from a hard surface with strong C-C covalent bonds into a soft surface with a metal carbon complex (i.e., C=Fe=C bonds) during CMP, resulting in a remarkable increase in the rate of the SOC film surface transformation with an increase in ferric catalyst concentration. However, this surface transformation on the SOC film surface resulted in a noticeable increase in the absorption degree (i.e., hydrophilicity) of the SOC film CMP slurry on the polished SOC film surface during CMP. The polishing rate of the SOC film surface decreased notably with increasing ferric catalyst concentration. Therefore, the maximum polishing rate of the SOC film surface (i.e., 272.3 nm/min) could be achieved with a specific ferric catalyst concentration (0.05 wt%), which was around seven times higher than the me-chanical-only CMP.
RESUMEN
For scaling-down advanced nanoscale semiconductor devices, tungsten (W)-film surface chemical mechanical planarization (CMP) has rapidly evolved to increase the W-film surface polishing rate via Fenton-reaction acceleration and enhance nanoscale-abrasive (i.e., ZrO2) dispersant stability in the CMP slurry by adding a scavenger to suppress the Fenton reaction. To enhance the ZrO2 abrasive dispersant stability, a scavenger with protonate-phosphite ions was designed to suppress the time-dependent Fenton reaction. The ZrO2 abrasive dispersant stability (i.e., lower H2O2 decomposition rate and longer H2O2 pot lifetime) linearly and significantly increased with scavenger concentration. However, the corrosion magnitude on the W-film surface during CMP increased significantly with scavenger concentration. By adding a scavenger to the CMP slurry, the radical amount reduction via Fenton-reaction suppression in the CMP slurry and the corrosion enhancement on the W-film surface during CMP performed that the W-film surface polishing rate decreased linearly and notably with increasing scavenger concentration via a chemical-dominant CMP mechanism. Otherwise, the SiO2-film surface polishing rate peaked at a specific scavenger concentration via a chemical and mechanical-dominant CMP mechanism. The addition of a corrosion inhibitor with a protonate-amine functional group to the W-film surface CMP slurry completely suppressed the corrosion generation on the W-film surface during CMP without a decrease in the W- and SiO2-film surface polishing rate.
RESUMEN
Recently, great advances of the Li-S battery technology have enabled its penetration as the power source of mid- and large-sized devices, which require high energy and power density that cannot be achieved with Li-ion batteries. While the most successful Li-S battery operation is enabled by the tailoring of the sulfur composite cathode composite structure, the binder system has recently been considered as another important factor. We study the structural and electrochemical performance of sulfur cathodes prepared with two different binders. Enhanced battery performance is observed in the SBR/CMC-based electrode and its origin is scrutinized.
RESUMEN
Si nanoparticles uniformly coated with Co-containing N-doped carbon were investigated as an anode material for Li-ion batteries. The Si nanoparticle surfaces were modified with conductive and matrix, N-doped carbon and cobalt element and prepared by a simple pyrolysis process using an ionic liquid that contained nitrogen with metal complex. After a simple annealing process, the N-doped carbon containing cobalt element was uniformly coated onto the Si nanoparticles. The smooth carbon layer connected the Si nanoparticles without any morphological changes. Si nanoparticles containing 34 wt% N-doped carbon and cobalt element exhibited a stable electrochemical performance with a capacity of ~1133 mAh g-1 and excellent capacity retention over 60 cycles. The high electrochemical performances was attributed to the synergistic effect by presence cobalt in N-doped carbon matrix, which alleviated the lithium-silicon alloying reaction-induced volume expansion and enhanced electrical conductivity during cycling.
RESUMEN
Nano-metal with nano-thin exfoliated (NTE) graphite hybrid material has been synthesized by radio frequency (RF) thermal plasma. A micro-sized nickel powder and the NTE graphite powder were fed into the RF plasma and nano sized nickel particles attached to the surface of the NTE graphite were found. In the high temperature of RF thermal plasma that is of higher than 10,000 K, the NTE graphite was not vaporized or damaged, while the metal powder was vaporized. The size of nickel nanoparticles on the NTE graphite was 40 80 nme. The size and number density of produced metal nanoparticle can be controlled by the process pressure in a reactor, the feeding ratio of raw materials, and the flow rate of working gas. X-ray diffraction results of the produced hybrid nano material indicate that there was a bonding between the nano metal and the NTE graphite. The inert nature of surface of the NTE graphite has been a barrier for the NTE graphite to be used a compounding additive. The nano metal covered NTE graphite will open up many potential applications of NTE graphite and polymer compound materials.