Observation and analysis of the irradiation temperature dependence in the formation efficiency of the irradiation-induced defects in SiC aid its related materials

单晶碳化硅（SiC）是宽禁带半导体（WGS）的一种，有望成为在高温和极低温强辐射场（电子、中子、质子等）等恶劣环境下工作的电子器件的优良材料。在不同温度下用反应堆辐射或电子辐照样品。用光学光谱和电子自旋共振（ESR）方法观察了辐照效应。这些结果总结如下：1）已经发现由于辐照而在n型SiC中形成的Si空位型缺陷的形成效率的辐照温度依赖性（ITD）不同于通常建立的理论。用电子自旋共振（ESR）和光电子能谱（OS）都观察到，在10 ~ 370 K之间，在200 K附近有一个最大值。另一方面，还发现在作为共价键合材料的金红石（TiO 2）和AlN中存在与SiC类似的ITD。2）然而，在p型SiC中并不能清楚地得到类似的现象。认为这是由于SiC中受主硼的（n，α）反应所引起的核加热掩盖了对辐照温度的影响; 3）<31>SiC中的核转变掺杂对引入的~ 2 P施主的影响是有效的; 4）中子辐照使p型SiC转变为n型SiC。

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.