Preparation of polycrystalline SiC films by dry process and their application to thin film transistors

本研究的主要内容如下：1.碳化硅薄膜的制备：采用反应溅射法制备了多晶碳化硅薄膜。靶材是由单晶硅片制成的。反应气体为CH4。衬底温度必须高于700ﾟC才能获得高质量的薄膜。用碳带加热器获得了高于700ﾟ的衬底温度。晶体结构特征：用X射线衍射仪和电子束衍射仪表征了薄膜的晶体结构。结果表明，采用这种方法可以将衬底温度降低到700ﾟC。化学性质：XPS测试表明，Si/C比不仅受CH4S分压的影响，还受总压力的影响。4.电学性能：通过光吸收测试和霍尔测试对薄膜进行了表征。霍尔测量结果表明，当沉积温度为750ﾟC时，薄膜的质量最好。导电类型的控制：作为受主杂质的铝比作为受主杂质的硼更有效地控制了薄膜的导电类型。6.在薄膜晶体管和其他器件上的应用：利用多晶硅制作薄膜晶体管、压力传感器和流量传感器。碳化硅薄膜，以显示其在电子器件中的适用性。

The summary of this research report is as follows ;1.Preparation of SiC Films : Polycrystalline SiC films were deposited by reactive sputtering. The target was made from a single crystal Si wafer. The reactive gas was CH_4. The substrate temperature must be higher than 700ﾟC to obtain a high quality film. A heater made from carbon ribbon was used to obtain higher substrate temperature than 700ﾟC.2.Characterization of Crystal Structure : Crystal structure of the films was characterized by X-ray diffraction and electron beam diffraction. The sample was polycrystalline when they were deposited at higher temperature than 700ﾟC.The results showed that it was possible by this method to reduce the substrate temperature to 700ﾟC.3.Chemical Properties : XPS measurement showed that the ratio of Si/C was affected not only by the partial pressure of CH_4s but also by the total pressure.4.Electrical Properties : The films were characterized by photo-absorption measurement and Hall measurement. The value of absorption edge was almost the same to the value of 3C-SiC.The results of hall measurement showed that the best quality for the application to TFT was obtained when the films were deposited at 750ﾟC.5.The Control of Conduction Type : Aluminum was more effective than boron as the acceptor impurity to control the conduction type.6.Application to TFT and Other Devices : Thin film transistors, pressure sensors and flow sensors were fabricate using the polycrystalline. SiC films to show its applicability to electronic devices.