Preparation of Ceramics Coating Films and Surface Modification by Controlled Plasmas

FCR等离子沉积装置于1988年建成。在该装置上安装了光学发射光谱仪和静电探头，用于等离子体诊断。样品可以加热到800ﾟC，并偏置到所需的粒子种类以轰击基片。通过改变放电压力、微波功率、衬底偏压和温度，进行了一系列的锆、钛和钽的氮化实验。将氮气等离子体氮化样品与常规气体氮化样品进行了比较。用俄歇电子能谱仪测定了渗层表面的氮含量，发现等离子体渗氮比气体渗氮更有效。尤其是在较低的温度(500-600ﾟC)下，氮等离子体对材料表面也有很好的氮化效果。随着放电压力的降低，离子物种相对占优势，而氮自由基物种相对占优势。在这种情况下，离子物种的硝化反应进行得很好。虽然人们认为氮自由基对硝化反应是有效的，但本实验表明离子物种对硝化反应非常有效。然后，我们尝试通过在衬底上施加负电压来增强离子种类。随着离子通量，即负偏压的增加，硝化反应进行。实验表明，受控等离子体对表面改性有较大的调节作用。

FCR plasma Deposition Device had been constructed in 1988. Optical emission spectrometer and electro-static probe have been attached to this apparatus for plasma diagnostics. The sample can be heated up to 800ﾟC and be biased to for desirable particle species to bombard on the substrate. By changing discharge pressure, microwave power, substrate bias and temperature, we had a series of nitrization experiments for Zr, Ti and Ta. The nitrized sample due to nitrogen plasma was compared with that due to usual gas nitrization. The nitrogen content at the surface was determined by Auger Electron Spectroscopy.It was observed that the plasma nitrization was more effective than the gas nitrization. In particular, the material surface was well nitrized by nitrogen plasmas even at lower temperature (500-600ﾟC). As the discharge pressure was reduced, the ion species relatively became dominant than the nitrogen radical species. In this case, the nitrization very well progressed by the ion species. Although it was believed that the nitrogen radical was effective for nitrization, the present experiment showed that ion species was very effective for the nitrization. We then tried to enhance the ion species by applying negative voltage to the substrate. The nitrization progressed as the increase of ion flux, i.e. negative bias potential. This experiment showed that the surface modification could be considerably adjusted by the controlled plasma.