目的 研究不同氮气浓度对氮掺杂纳米金刚石薄膜结构和电学性能的影响。方法 在N2-CH4-H2体系中，以单晶硅作为沉积基底，使用MPCVD法进行纳米金刚石膜的沉积。采用扫描电子显微镜对所沉积的纳米金刚石膜的表面形貌进行表征，采用拉曼光谱对纳米金刚石膜的质量进行表征，采用X射线衍射对纳米金刚石的N原子构型进行研究，采用电化学工作站对纳米金刚石膜表面电学性能进行表征。结果 N2浓度上升，线状纳米金刚石平均线长降低，在90%时转变为团聚状纳米金刚石晶粒。N2浓度上升，H2浓度下降，纳米金刚石膜的sp2键含量先上升后下降。随着氮气浓度的上升，纳米金刚石膜的晶粒尺寸先减小后增大，在85%时最小，为12.6 nm；表面电阻先下降后上升，在85%时最低，为9.2 Ω。XPS高分辨率N1s结果表明，具有导电性能的吡啶氮和吡咯氮的含量随氮气浓度上升的变化趋势相反，但两者之和保持不变。结论 纳米金刚石膜的电学性能主要受其平均晶粒尺寸的影响，晶粒尺寸降低，则晶界含量上升，电学性能上升；晶粒尺寸下降，则晶界含量下降，电学性能下降。

The work aims to study effects of different nitrogen concentration on structure and electrical properties of N-doped nano-crystalline diamond (NCD) films. Single crystal silicon was used as substrate and N-doped NCD films were deposited in MPCVD method in N2-CH4-H2 gas system. Surface morphology of the deposited films was characterized by SEM. Quality of the NCD films was characterized by Raman spectra, N atom configuration of the deposited NCD films was studied based upon X-ray diffraction, and electrical properties of the NCD films were characterized by electrochemical workstation. Average length of the linear NCD decreased as N2 concentration increased, and the linear NCD transformed into aggregated NCD grains at the N2 concentration of 90%. H2 concentration decreased, and sp2 content first increased and then decreased as N2 concentration increased. Grain size of the NCD films first decreased and then increased, and reached the minimum (12.6 nm) at the N2 concentration of 85%. According to the electrical test results, surface resistance of the NCD films first decreased and then increased as the N2 concentration increased, and reached the minimum (9.2 Ω) at the N2 concentration of 85%. XPS high resolution N1s results showed that variation trend of conductive pyridinic-N was opposite to that of conductive pyrrolic-N as N2 concentration increased. Electric properties of NCD films are mainly affected by average grain size of the films. The decrease of grain size leads to increase of crystal boundary content and electrical properties, and the increase of grain size leads to decrease of crystal boundary content and electrical properties.