低浓度氮气对MPCVD法制备金刚石膜的影响

Influence of low N_2 concentration on growth of diamond films by MPCVD

利用微波等离子体化学气相沉积(MPCVD)法,在CH4/H2的混合反应气源中加入N2进行了金刚石膜的沉积实验,详细研究了N2浓度对金刚石膜生长的影响规律。使用扫描电子显微镜、激光拉曼光谱仪和X射线衍射仪等设备,表征了金刚石薄膜的表面形貌、相组成及晶面取向。实验结果表明:随着N2体积分数的增加(由0%增加到6%),薄膜中的非金刚石相含量逐渐增大,金刚石晶粒尺寸逐渐减小,晶面取向也由较大的晶面(111)转变成较小的晶面(100);当N2体积分数为4%时,沉积的金刚石膜表面为"菜花"状结构;低体积分数(2%)的N2有利于获得高度取向(100)的金刚石膜。

Diamond films deposition were implemented through microwave plasma chemical vapor deposition（MPCVD）method using mixed gas of CH4/H2/N2.Influence of N2 on diamond films was studied in detail.Scanning electron microscope（SEM）,laser Raman spectroscopy and X-ray diffraction（XRD）were used to observe the surface morphology,the phase composition and the crystal orientation of diamond films.Results showed that the content of amorphous diamond phase in the film increased with the enlargement of N2 volume concentration（from 0% to 6%）,but the diamond grain size presented a downward trend.Meanwhile,the crystal orientation of larger（111）crystal plane transforms into smaller（100）crystal plane.It is more conducive to obtain diamond films with high（100）crystal plane under a relatively low N2concentration（about 2%）,while it turns up a kind of ＂cauliflower＂ structure when N2 concentration was 4%.