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New method for computer numerical control machine tool calibration: Relay method

LIU Huanlao, SHI Hanming, LI Bin, ZHOU Huichen

《机械工程前沿（英文）》 2007年第2卷第3期页码 301-304 doi: 10.1007/s11465-007-0053-3

摘要： Relay measurement method, which uses the kilogram-meter (KGM) measurement system to identify volumetric errors on the planes of computer numerical control (CNC) machine tools, is verified through experimental tests. During the process, all position errors on the entire plane table are measured by the equipment, which is limited to a small field. All errors are obtained first by measuring the error of the basic position near the original point. On the basis of that positional error, the positional errors far away from the original point are measured. Using this analogy, the error information on the positional points on the entire plane can be obtained. The process outlined above is called the relay method. Test results indicate that the accuracy and repeatability are high, and the method can be used to calibrate geometric errors on the plane of CNC machine tools after backlash errors have been well compensated.

关键词： positional volumetric information process repeatability

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Statistical analysis of recombination properties of the boron-oxygen defect in p-type Czochralski silicon

Nitin NAMPALLI,Tsun Hang FUNG,Stuart WENHAM,Brett HALLAM,Malcolm ABBOTT

《能源前沿（英文）》 2017年第11卷第1期页码 4-22 doi: 10.1007/s11708-016-0442-6

摘要： This paper presents the application of lifetime spectroscopy to the study of carrier-induced degradation ascribed to the boron-oxygen (BO) defect. Specifically, a large data set of p-type silicon samples is used to investigate two important aspects of carrier lifetime analysis: ① the methods used to extract the recombination lifetime associated with the defect and ② the underlying assumption that carrier injection does not affect lifetime components unrelated to the defect. The results demonstrate that the capture cross section ratio associated with the donor level of the BO defect ( ) vary widely depending on the specific method used to extract the defect-specific recombination lifetime. For the data set studied here, it was also found that illumination used to form the defect caused minor, but statistically significant changes in the surface passivation used. This violation of the fundamental assumption could be accounted for by applying appropriate curve fitting methods, resulting in an improved estimate of (11.90±0.45) for the fully formed BO defect when modeled using the donor level alone. Illumination also appeared to cause a minor, apparently injection-independent change in lifetime that could not be attributed to the donor level of the BO defect alone and is likely related to the acceptor level of the BO defect. While specific to the BO defect, this study has implications for the use of lifetime spectroscopy to study other carrier induced defects. Finally, we demonstrate the use of a unit-less regression goodness-of-fit metric for lifetime data that is easy to interpret and accounts for repeatability error.

关键词： Czochralski silicon boron-oxygen defect injection dependent lifetime spectroscopy goodness-of-fit repeatability error