集成电路中的晶化点缺陷分析

晶化点是集成电路金属化工艺中温度过高、合金导电性差的一种征兆,也会导致集成电路出现开路、短路等失效情形。总结了集成电路中晶化点缺陷的形成机理,对产生晶化点的工艺原因进行了探讨,并结合工程案例对晶化点缺陷导致的集成电路失效情形及有关失效机理进行了分析。最后,从工艺上提出若干改进这一缺陷的建议。

Electrochemical corrosion properties of Zr- and Ti-based bulk metallic glasses

The corrosion behaviors of Ti-based and Zr-based amorphous alloys and their corresponding crystallized alloys were studied by electrochemical methods. It is found that the corrosion potentials of Zr-based amorphous alloy and its corresponding crystalline counterpart are both lower than those of the Ti-based amorphous alloy in the 1 mol/L H2SO4 solution. In the 3.5% NaCl solution,Zr-based crystallized alloy exhibits the lowest corrosion potential among the experimental samples. No passivation is observed in the corrosion process for the Zr-based crystalline alloy. However, Zr- and Ti-based amorphous alloys both exhibit passivation characteristics. EIS measurements indicate the amorphous alloys exhibit better corrosion resistance than the crystallized one in the NaCl solution. Surface analysis shows that both amorphous alloys in the NaCl solution are eroded by pitting corrosion. In the H2SO4 solution, all the alloys display similar behaviors and their surfaces can mostly keep intact except for some cracks on the corroded surface at local region.

Preparation and Characterization of Fe Nanowire Arrays Embedded in Porous Anodic Aluminum Oxide Templates

Fe nanowire arrays are prepared by electrodeposition in porous anodic aluminum oxide template from a composite electrolyte solution. These nanowires have an uniform diameter of approximate 25 nm and a length in excess of 2.5 μm. The micrographs and crystal structures of Fe nanowires are studied by transmission electron microscopy (TEM), selected-area electron diffraction (SAED), and X-ray diffraction(XRD). It is found that each nanowire is essentially a single crystal and has a different orientation in each array. Hysteresis loops of Fe nanowire array show that its easy magnetization direction is perpendicular to the sample plane.

Multi sites vs single site for catalytic combustion of methane over Co3O4(110):A first-principles kinetic Monte Carlo study

Single-atom catalysts have been applied in many processes recently.The difference of their kinetic behavior compared to the traditional heterogeneous catalysts has not been extensively discussed yet.Herein a complete catalytic cycle of CH4 combustion assuming to be confined at isolated single sites of the Co3O4(110)surface is computationally compared with that on multi sites.The macroscopic kinetic behaviors of CH4 combustion on Co3O4(110)is systematically and quantitatively compared between those on the single site and multi sites utilizing kinetic Monte Carlo simulations upon the energetic information from the PBE+U calculation and statistic mechanics.The key factors governing the kinetics of CH4 combustion are disclosed for both the catalytic cycles respectively following the single-site and multi-site mechanisms.It is found that cooperation of multi active sites can promote the activity of complete CH4 combustions substantially in comparison to separated single-site catalyst whereas the confinement of active sites could regulate the selectivity of CH4 oxidation.The quantitative understanding of catalytic mechanism paves the way to improve the activity and selectivity for CH4 oxidation.

Fabrication and Properties of Microencapsulated n-octadecane and Paraffin

Microencapsulated n-alkanes as energy- storage materials have promising application prospects. The ndcrocapsules containing 100 - 50 wt% of n - octadecane, 0 -20 wt% of paraffin and 0 - 30 wt% of cyclohexane were synthesized by in-situ polymerization using melamine- formaldehyde polymer as shell. Cyclohexane was removed after heat-treated the microcapsules at 100℃. The morphologies, cell parameters, phase change properties, thermal stable temperatures of these microcapsules were examined. The diameters of these microcapsules are lower than 5 μm. The effect of paraffin in the microcapsules on the cell parameters of n-octadecane is negligible. The paraff＇m is effectively used as a nucleating agent to decrease the degree of supercooling. The melting enthalpy is decreased from 132 J/g to 111 J/g due to the increase of the cyclohexane contents. The thermal stable temperature is enhanced 6 - 16℃ after heat-treated the microcapsules at 160℃ for 30 min.

Refinement and strengthening mechanism of Mg−Zn−Cu−Zr−Ca alloy solidified under extremely high pressure

Mg−Zn−Cu−Zr−Ca samples were solidified under high pressures of 2-6 GPa.Scanning electron microscopy and electron backscatter diffraction were used to study the distribution of Ca in the microstructure and its effect on the solidification structure.The mechanical properties of the samples were investigated through compression tests.The results show that Ca is mostly dissolved in the matrix and the Mg_(2)Ca phase is formed under high pressure,but it is mainly segregated among dendrites under atmospheric pressure.The Mg_(2)Ca particles are effective heterogeneous nuclei ofα-Mg crystals,which significantly increases the number of crystal nuclei and refines the solidification structure of the alloy,with the grain size reduced to 22μm at 6 GPa.As no Ca segregating among the dendrites exists,more Zn is dissolved in the matrix.Consequently,the intergranular second phase changes from MgZn with a higher Zn/Mg ratio to Mg7Zn3 with a lower Zn/Mg ratio.The volume fraction of the intergranular second phase also increases to 22%.Owing to the combined strengthening of grain refinement,solid solution,and dispersion,the compression strength of the Mg-Zn-Cu-Zr-Ca alloy solidified under 6 GPa is up to 520 MPa.

Effects of Thermal Lattice Vibration on the Effective Potential of Weak-Coupling Bipolaron in a Quantum Dot

Based on the Huybrechts' linear-combination operator,effects of thermal lattice vibration on the effective potential of weak-coupling bipolaron in semiconductor quantum dots are studied by using the LLP variational method and quantum statistical theory.The results show that the absolute value of the induced potential of the bipolaron increases with increasing the electron-phonon coupling strength,but decreases with increasing the temperature and the distance of electrons,respectively;the absolute value of the effective potential increases with increasing the radius of the quantum dot,electron-phonon coupling strength and the distance of electrons,respectively,but decreases with increasing the temperature;the temperature and electron-phonon interaction have the important influence on the formation and state properties of the bipolaron:the bipolarons in the bound state are closer and more stable when the electron-phonon coupling strength is larger or the temperature is lower;the confinement potential and coulomb repulsive potential between electrons are unfavorable to the formation of bipolarons in the bound state.

Influences of spin on the properties of a weak-coupled magnetopolaron in quantum dot

Considering the influences of the spin on the ground state energy,the properties of a weak-coupled magnetopolaron in quantum dots are studied by using a linear combination operator and unitary transformation method.The numerical calcu-lation results for CaP crystals have been given as examples.

Nanocrystal-semiconductor interface： Atomic-resolution cross-sectional transmission electron microscope study of lead sulfide nanocrystal quantum dots on crystalline silicon

We report on a cross-sectional high resolution transmission electron microscope study of lead sulfide nanocrystal quantum dots （NCQDs） dispersed on electron-transparent silicon nanopillars that enables nearly atomically-resolved simultaneous imaging of the entire composite： the quantum dot, the interfacial region, and the silicon substrate. Considerable richness in the nanocrystal shape and orientation with respect to the substrate lattice is observed. The average NCQD-substrate separation is found to be significantly smaller than the length of the ligands on the NCQDs. Complementary photoluminescence measurements show that light emission from PbS NCQDs on silicon is effectively quenched which we attribute to intrinsic mechanisms of energy and charge transfer from PbS NCQDs to Si.