Studying the micromechanical properties of gas-bearing shale is very important for understanding it. In the nanoindentation measurement of gas-bearing shale, the load-displacement curve often shows pop-in at the loading stage, namely the change of load is small but the change of penetration depth is large. Pop-in can introduce a large error in the calculation of the mechanical parameter. To investigate the influence factors of pop-in, the maximum load, load rate and sample characteristics have been addressed. The results show that pop-in is related to cracks and pores in the shale. Due to the heterogeneity of shale, pop-in cannot be avoided, but can be reduced by choosing reliable load modes and test parameters. Pop-in can increase the maximum indentation depth and decrease the elastic modulus and hardness. The influence of pop-in on hardness is larger than on the elastic modulus. At a high load rate it is easy to induce pop-in. The influence of the load rate on pop-in is larger than that of the maximum load.
Direct coupling of optical power from a conventional dielectric waveguide to a photonic crystal waveguide is analyzed by the finite-difference time-domain (FDTD) method in this work. It is well known that the coupling efficiency is dependent on the wavelength, the structural parameters of waveguides, the small gap between the waveguides, and so on. And we find out that the wavepacket curve of the coupling efficiency decreases as the gap increases. The coupling-efficiency curve has two oscillatory periods. The wave packet is resulting from the Fabry-Perot resonances within the gaps between the facet of the conventional optical waveguide and the distinct-layer pillars in the photonic crystal waveguide.
In the field of failure analysis, electrical failures caused by improper implantation are often difficult to debug especially for fully processed products. Familiar implantation failure issues include improper implantation concentration, error doping types, incorrect doping ranges, and etc. Although some FA equipments, such as secondary ion mass spectrometry (SIMS), spreading resistance probe (SRP) and scanning capacitance microscope (SCM) [1] [2] [3], can do detail or quantitative analysis for these failure issues, most of these FA jobs are time-consuming and have a detection limitation at the size of failure area. This limitation may restrict the FA applications because the failure area is usually small at the fully processed products after fault isolation. In this paper, two examples with improper doping type and concentration will be analyzed by using a newly developed FA method. Instead of using traditional cross-section (X-S) stain method, we utilize a plane-view stain method to compare the doping type and doping concentration between normal and failed regions. With the aid of the plane-view stain method, we can have a quick check at the suspected failure area with improper front-end implantation before specific SCM analysis.
A dual beam FIB (Focused Ion Beam) system which provides the ion beam (i-beam) and electron beam (e-beam) function are widely used in semiconductor manufacture for construction analysis and failure cause identification. Although FIB is useful for defect or structure inspection, sometimes, it is still difficult to diagnose the root cause via FIB e-beam image due to resolution limitation especially in products using nano meter scale processes. This restriction will deeply impact the FA analysts for worst site or real failure site judgment. The insufficient e-beam resolution can be overcome by advanced TEM (Transmission Electron Microscope) technology, but how can we know if this suspected failure site is a real killer or not when looking at the insufficient e-beam images inside a dual beam tool? Therefore, a novel technique of device measurement by using C-AFM (Conductive Atomic Force Microscope) or Nano-Probing system after cross-sectional (X-S) FIB inspection has been developed based on this requirement. This newly developed technology provides a good chance for the FA analysts to have a device characteristic study before TEM sample preparation. If there is any device characteristic shift by electrical measurement, the following TEM image should show a solid process abnormality with very high confidence. Oppositely, if no device characteristic shift can be measured, FIB milling is suggested to find the real fail site instead of trying TEM inspection directly.
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