| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2002: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Research Abstract |
Single crystalline silicon carbide (SiC), which is one of wide-gap semiconductors (WGS), is expected to be an excellent material by way of electronic devices acting under severe environment such as intense radiation field (electron, neutron, proton, etc) with high temperature and extreme low temperature. Samples were irradiated in various temperatures with reactor radiations or electrons. The radiation effects were observed by using the method of the optical spectroscopy (OS) and the ESR. The related materials such as nitrides, oxides and other WGS's were also examined These results are summarized following.
1) It has been found that the irradiation temperature dependence (ITD) of the formation efficiency of the Si-vacancy-type-defect formed in n-type SiC due to the irradiation was different from the usual established theory. It was observed by both of the OS and the ESR that it had the maximum value at about 200K between 10K and 370K. On the other hand, it has been also found that there is the ITD similar to SiC, in rutile (TiO2) and AIN, which are a covalent bonding material. From these facts, we proposed that it does cause to the covalent bonding.
2) However, in the p-type SiC it could not clearly get the similar phenomenon. It was thought because the effect on irradiation temperature was covered by a nuclear heating which was caused to the (n, α) reaction of acceptor boron in SiC.
3) It has been found that the effect on ^<31>P donor introduced by the nuclear-transformation-doping in SiC is effective.
4) The p-type SiC was changed into the n-type one due to neutron irradiation.
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