采用等离子体增强化学气相生长技术制备立方氮化硼薄膜,系统研究了背底真空度和生长过程中氧气的存在对立方氮化硼薄膜中氧杂质含量的影响.发现把背底真空度提高至1×10^-5Pa仍然不能有效消除立方氮化硼薄膜中的氧杂质.随着立方氮化硼薄膜中氧杂质的增加,其红外吸收谱的Lorentz拟合发现,在1230~1280cm^-1附近出现由氧原子与硼原子结合形成的B-O键的反对称伸缩振动引起的吸收峰.该吸收峰的强度与薄膜中的氧杂质含量有较好的线性关系,因此可以通过分析该吸收峰的强度半定量地测定立方氮化硼薄膜中的氧杂质含量。
Cubic boron nitride thin films were prepared by inductively-coupled plasma-enhanced chemical vapor deposition(ICP-CVD).The influences of base pressure and oxygen concentration on the content of oxygen impurity for cubic boron nitride film deposition were investigated.It was found that approximately 2% of oxygen impurity can still be detected in cubic boron nitride films even under a base pressure of up to 1×10^-5Pa.Moreover,a new infrared(IR) absorption peak near 1230-1280 cm^-1 was detected by Lorentzian-type curve fitting when the oxygen impurity content reached more than 3 at%.O1s core-level X-ray photoelectron spectroscopy(XPS) measurements confirmed the existence of B-O bond in boron nitride films.Therefore,this new peak could be attributed to the antisymmetric B-O stretching vibration of the trigonal BO3 group.Moreover,the intensity of this new peak was found to increase with oxygen impurity concentration linearly.Thus the oxygen impurity content in cubic boron nitride films could be evaluated quasi-quantitatively from the intensity of this new IR absorption peak.