基片温度对纳米金刚石薄膜掺硼的影响

采用微波等离子体化学气相沉积法,以氢气稀释的乙硼烷为硼源进行了纳米金刚石(NCD)薄膜的生长过程掺硼,研究了基片温度对掺硼NCD薄膜晶粒尺寸、表面粗糙度、表面电阻和硼原子浓度的影响.利用扫描电子显微镜和原子力显微镜观察NCD薄膜的表面形貌,并通过Imager软件对原子力显微镜数据进行分析获得薄膜的表面粗糙度及平均晶粒尺寸信息;采用四探针测量掺硼NCD薄膜的表面方块电阻,利用二次离子质谱仪对掺杂后NCD薄膜表面区域的硼原子浓度进行测量.实验结果表明,较高的基片温度有利于提高薄膜的导电能力,但随着基片温度的提高,NCD薄膜的平均晶粒尺寸和表面粗糙度逐渐增大;此外,当反应气体中的乙硼烷浓度一定时,掺杂后NCD薄膜的表面硼原子浓度随基片温度升高存在一个饱和值.在所选乙硼烷浓度为0.01%的条件下,基片温度在700℃左右可以在保证薄膜表面电性能的基础上保持较好的表面形貌.

Influence of substrate temperature on boron-doping of nano-crystalline diamond films

Nano-crystalline diamond （NCD） films were boron doped by microwave plasma enhanced chemical vapor deposition method using hydrogen diluted di-borane as boron source. The influences of substrate temperature on grain size, surface roughness, surface resistance and boron atom concentration of boron-doped NCD films were researched. Scanning electron microscope and atomic force microscope （AFM） were used to observe the surface morphology of boron-doped NCD films,while the grain size and surface roughness information were obtained by disposing the AFM data using Imager software. Four point probe was used to detect the surface resistance and secondary ion mass spectrometer was uti- lized to test the boron atom concentration. Results show that higher substrate temperature is propitious to enhance the electrical conductivity, but it still leads to big grains and rough surface. In addition, there is a saturated boron atom concentration during the rising of substrate temperature when the di-borane concentration is confirmed. In this work, to obtain good electrical properties and smooth uniform sur- face,it＇s better to maintain substrate temperature at 700℃ when the di-borane concentration is con- firmed at O. 01%.