大型变压器渗漏油故障的查找及处理

简单阐述了油浸式变压器渗漏油的原因及查找方法 ,并介绍了处理变压器渗漏油的几种方法。     

Ge volatilization products in high-k gate dielectrics

GeO molecules are often emitted by Ge substrates under high-temperature annealing and, in the case of gate stacks, they diffuse through high-k oxides. Here we use first-principles quantum-mechanical calculations to probe the stability of these impurities in La₂O₃ and HfO₂ and their effect on the electronic properties of the host systems. We find that the GeO species introduce several different levels inside the energy band gaps of La₂O₃ and HfO₂. As a result, the impurities may act as charge carrier traps. Hydrogenation of the GeO defects modifies the position and numbers of gap states, but does not eliminate the carrier trap levels completely. The results suggest a possible role of Ge volatilization in enhancing leakage currents and degradation in high-k gate stacks of Ge-based devices.     

仪表气漏入工艺管道导致空分装置停车

介绍了主换热器换热不良、主冷液面维持不住 ,空分装置被迫停车的故障现象及原因 ;通过分析 ,仪表气自保系统发生故障 ,使含有大量二氧化碳的仪表气串入分子筛吸附器后的工艺空气中 ,是导致主换热器换热不良的原因 ;并提出了几点操作上的教训     

Capacitance measurements and k-value extractions of low-k films

We review test vehicles and methods that are commonly used for capacitance measurements of low-k films and the general procedure for k-value extractions. We demonstrate that a considerable loss of accuracy may occur if metal-insulator-semiconductor (MIS) planar capacitors are used in high frequency (HF) capacitance-voltage (CV) measurements leading to significant underestimation of the k-value. We show that the lack of accuracy is due to parasitic impedance at the backside connection with the Si substrate and we provide a model. The effect of the parasitic impedance can be minimized by reducing the area of the gate electrode. Alternatively, samples can be provided with an ohmic back contact by means of one of the practical fabrication methods that are described. Quasi-static (Q-S) CV measurements did not exhibit any variation related to backside connection. However, we show that Q-S CV measurements loose accuracy for plasma-damaged low-k films because of increased dielectric leakage. Finally, issues related to capacitance measurements in dry atmosphere are addressed. We show that long (∼hours) transients can take place for plasma-damaged low-k films because of the slow release of water from the material underneath the metal gate, which acts as a cap. As a consequence, extracted k-value can significantly depend on sample resident time in the measurement chamber and on gate dimensions.     

Grain boundary mediated leakage current in polycrystalline HfO2 films

In this work, we combine conductive atomic force microscopy (CAFM) and first principles calculations to investigate leakage current in thin polycrystalline HfO₂ films. A clear correlation between the presence of grain boundaries and increased leakage current through the film is demonstrated. The effect is a result of a number of related factors, including local reduction in the oxide film thickness near grain boundaries, the intrinsic electronic properties of grain boundaries which enhance direct tunnelling relative to the bulk, and segregation of oxygen vacancy defects which increase trap assisted tunnelling currents. These results highlight the important role of grain boundaries in determining the electrical properties of polycrystalline HfO₂ films with relevance to applications in advanced logic and memory devices.     

TN、TT接地系统在户外照明中的应用研究

通过对两种接地系统型式(TN、TT)的户外照明装置的接地故障保护的分析,得出了户外照明装置宜采用TT系统,应用漏电保护器作为接地故障的主保护,同时讨论了应用漏电保护器时应注意的问题。     

Optimization of electric properties of high-k zirconium dioxide by varying deposition and annealing conditions

ZrO₂ thin films with a smooth surface were synthesized on silicon by atomic vapor deposition™ using Zr[OC(CH₃)₃]₄ as precursor. The maximum growth rate (7 nm min⁻¹) and strongest crystalline phase were obtained at 400 °C. The increase of the deposition temperature reduced the deposition rate to 0.5 nm min⁻¹ and changed the crystalline ZrO₂ phase from cubic/tetragonal to monoclinic. These films showed no enhancement of the dominating monoclinic phase by annealing. The values of the dielectric constant (up to 32) and leakage current density (down to 1.2×10⁻⁶ A cm⁻² at 1×10⁶ V cm⁻¹) varied depending on the deposition temperature and film thickness. The midgap density of interface states was N_it=5×10¹¹ eV⁻¹ cm⁻². The leakage current and the density of interface states were lowered by the annealing to 10⁻⁷ A cm⁻² at 1×10⁶ V cm⁻¹ and to 10¹⁰ eV⁻¹ cm⁻², respectively. However, this also led to a decrease of the dielectric constant.     

大型电力变压器磁场分布及涡流损耗优化研究

对330kV油浸式电力变压器进行了磁场仿真计算研究。     

A Novel Bondpad report process for III-V semiconductor devices using full HSQ properties

This paper reports on an easy and quick planarization and passivation technique of III-V compound semiconductor compatible with nanoscale devices. Vertical etching requires good sidewalls passivation to reduce drastically the leakage current and to obtain a good planarization of the devices for metal connection. This novel technique offers the capability to planarize all the different compounds in the entire wafer independently of the height of the structure to be connected. This method uses the HSQ properties (fluidity, solidification to silica film by using O₂ plasma treatment, negative tone e-beam lithography resist, low-k dielectric, etc.) to planarize and to passivate all the devices at once. We applied this quick and easy method to InP digital optical switches. We demonstrated photonic switches with high yield (>90%), high breakdown voltage (>30 V), low ohmic contact resistance (8 Ω) and a low leakage current (21 pA/μm² for 5 V reversed bias).     

Influences of bottom electrode TaN on electrical characteristics for metal–HfO2–metal capacitors

For TaN–HfO₂–TaN_x capacitors, the effects of bottom electrode TaN_x with different nitrogen contents on electrical characteristics are exhibited. An obvious oxygen deficiency can be found in HfO₂ film by AES analysis for the sample with bottom electrode TaN_x sputtered at a N₂/(N₂ + Ar) flow ratio of 10%. The bottom electrode TaN_x films with different nitrogen contents apparently affect HfO₂/TaN_x interfacial property and electrical characteristic of follow-up deposited HfO₂ film. Experimental results reveal that the more defective TaN_x structure can induce more oxygen vacancies in subsequently deposited HfO₂ film and result in a higher leakage current density and a worse breakdown electric field. Two factors affect these electrical characteristics including interfacial stress and oxygen vacancy. It indicates that interfacial stress due to various stochiometric TaN_x structure dominates the voltage linearity property of capacitance, but more leak paths and local field breakdown defects can be induced by interfacial stress and oxygen vacancy. Better electrical characteristics can be attained for the sample with bottom electrode TaN_x sputtered at a N₂/(N₂ + Ar) flow ratio of 20%.