Papers by Author: Shohei Miyagawa

Abstract: Recently, the influence of heat conduction has been considered to be a big problem. Then, the influence of heat conduction was investigated by the experiment which changed the material, thickness of the specimen and frequency of a cyclic load. Then, the infrared hybrid method was developed to separate individual stress components. However, it has the influence by heat conduction in the infrared stress measuring method. Therefore, an error will arise in the infrared hybrid analysis. Then, the system which corrects the error by the inverse analysis was developed. Thereby, the accuracy of the stress intensity factor was able to be raised. Furthermore, the accuracy of hybrid method considering to heat conduction was discussed in comparison with the 3-D finite-element analysis and 2-D hybrid method.

Abstract: The thickness dependency of the temperature image obtained by an infrared thermography was investigated using specimens with three kinds of metal materials of different heat conduction and four kinds of thickness of the specimens. Then, the infrared hybrid method was developed to separate each stress components. However, it contains the influence of heat conduction in the infrared stress measurement method. Therefore, heat conduction error will arise in the infrared hybrid analysis. Then, the new system which corrects the error by an heat conduction inverse analysis was developed. Thereby, the accuracy of the stress intensity factor was able to be raised using heat conduction inverse analysis. Furthermore, the accuracy of hybrid method taking heat conduction into consideration was discussed in comparison with 3-D finite-element analysis and the 2-D infrared hybrid method.

Abstract: Influence of the frequency to the temperature image obtained by an infrared thermography was investigated using specimens of three kinds of materials at four kinds of frequencies of the cyclic load. Then, the infrared hybrid method was developed to separate individual stress components. However, the influence of heat conduction is inevitable in the infrared stress measurement method. Therefore, an error arises in the infrared hybrid analysis. Then, the system which corrects the error by the inverse analysis was developed. Thereby, the accuracy of the stress intensity factor was able to be raised. Furthermore, the accuracy of hybrid method considering to heat conduction was discussed in comparison with the 3-D finite element analysis and 2-D hybrid method.

Abstract: We developed EBAS-100, which is available to 100 mm diameter SiC wafer, for post ion implantation annealing in order to realize silicon carbide (SiC) device with large volume production. EBAS-100 is able to perform the rapid thermal process due to the vacuum thermal insulation and small heat capacity of susceptor. Electrical power consumption density was 18.8 Wh/cm2 for EBAS-100, which is one-third smaller than that of our previous system (EBAS-50). Samples used in this study were p-type epitaxial 4H-SiC (0001) grown on 8o off SiC substrate. P+ ions (total dose; 2.0 x 1016 /cm2, thickness; 350 nm) were implanted into SiC samples at 500 oC. The root-mean-square (RMS) of surface roughness is estimated to be 0.21 nm for the sample annealed at 1700 oC for 5 min, which is much smooth than that of the sample annealed by the conventional RF inductive annealing (RMS value: 5.97 nm). Averaged sheet resistance (RS) value of 63.3 ohm/sq. is obtained with the excellent non-uniformity of RS (+/- 1.4 %) for the diameter of 76.0 mm.

Abstract: The annealing behavior of the N+ implantation-induced defects in 4H-SiC(0001) has been investigated by means of Rutherford backscattering spectrometry in the annealing temperature range from 200 to 1000 oC. The samples are multiple-implanted by N+ ions with energy range from 15 to 120 keV at a total dose of 2.4 x 1015 /cm2. Three annealing stages are observed by isochronal annealing; first stage from 200 to 400 oC, second stage from 400 to 600 oC and third stage from 600 to 1000 oC. The 80 percent of the N+ implantation-induced defects are annealed out at the temperature above 600 oC. The annealing mechanism of the defects in each stage is discussed.

Abstract: The thickness dependency of the temperature image obtained by an infrared thermography was investigated using specimens with three kinds of materials and four kinds of the thickness of the specimen. Then, the infrared hybrid method was developed to separate individual stress components. However, it had the influence by heat conduction in the infrared stress measuring method. Therefore, an error will occur in the infrared hybrid analysis. Then, the system which corrected the error by the inverse analysis was developed. Thereby, the accuracy of the stress intensity factor was able to be raised. Furthermore, the accuracy of hybrid method considering to heat conduction was discussed in comparison with the 3-D finite-element analysis and 2-D hybrid method.