采用微波等离子体化学气相沉积(MPCVD)方法,通过改变CH_4浓度,在单晶Si(100)基底上制备掺氮纳米金刚石(NCD)薄膜,并以所制备的掺氮NCD薄膜为阴极材料,通过场发射扫描电子显微镜(FESEM)、原子力扫描探针显微镜(AFM)、Raman光谱和S波段射...采用微波等离子体化学气相沉积(MPCVD)方法,通过改变CH_4浓度,在单晶Si(100)基底上制备掺氮纳米金刚石(NCD)薄膜,并以所制备的掺氮NCD薄膜为阴极材料,通过场发射扫描电子显微镜(FESEM)、原子力扫描探针显微镜(AFM)、Raman光谱和S波段射频电子枪等测试方法系统地研究了掺氮NCD薄膜的微观结构对微波场发射性能的影响。结果表明:在CH_4浓度(体积比)为4%下,制备的掺氮NCD薄膜的颗粒呈多面体,而且颗粒尺寸和表面粗糙度较大,薄膜中金刚石相含量较高,这些微观结构使得微波场发射性能较高,在电场强度(E_0)为67.7 V·μm^(-1)时,发射电流密度(J0)高达144.8 m A·cm^(-2)。当升高CH_4浓度,所制备的掺氮NCD薄膜的颗粒尺寸减小而且连成条状结构,表面粗糙度也逐渐降低,薄膜中金刚石相减少、非金刚石相增加,这些微观结构的改变使得微波场发射性能逐渐降低。如当CH_4浓度增加至6%时,在电场强度E_0=67.7 V·μm^(-1)时,场发射电流密度降至37.9 m A·cm^(-2)。结果表明:低CH_4浓度下,掺氮NCD薄膜所具有的微观结构有利于微波场发射。展开更多
采用微波等离子体化学气相沉积(MPCVD)系统,在单晶硅基底上,以三聚氰胺为氮源实现纳米金刚石(NCD)薄膜N原子掺杂,并通过控制反应气体的压力制备出不同条件的掺氮NCD薄膜。用场发射电子显微镜(FESEM)、原子力探针显微镜(AFM)和激光拉曼光...采用微波等离子体化学气相沉积(MPCVD)系统,在单晶硅基底上,以三聚氰胺为氮源实现纳米金刚石(NCD)薄膜N原子掺杂,并通过控制反应气体的压力制备出不同条件的掺氮NCD薄膜。用场发射电子显微镜(FESEM)、原子力探针显微镜(AFM)和激光拉曼光谱(Raman)分析了不同气压对掺氮NCD薄膜表面形貌和物相成分的影响。结果显示:当压力由8 k Pa增加至12 k Pa时,薄膜颗粒尺寸减小,颗粒之间更加致密;表面粗糙度(RMS)也由90.4nm减少至40.4 nm;薄膜中金刚石相逐渐向SP2相转化。继续增加压力至15 k Pa时,薄膜颗粒尺寸呈增加趋势,并且分布不均匀;RMS也增加至131.5 nm;同时薄膜中SP2相含量达到最高。对12 k Pa条件下制备的掺氮NCD薄膜样品进行光电子能谱(XPS)检测,表明薄膜主要以SP2相碳含量为主,并且氮掺杂含量可达2.73%。展开更多
The microscopic mechanical characteristics of ultranano-crystalline diamond films which were prepared in four different atmospheres were investigated for the applications in microelectron-mechanical system（MEMS）.The...The microscopic mechanical characteristics of ultranano-crystalline diamond films which were prepared in four different atmospheres were investigated for the applications in microelectron-mechanical system（MEMS）.The loading-unloading curves and the change of modulus and hardness of samples along with depth were achieved through nanoindenter.The results show that the films which are made in atmosphere without Ar have the highest recovery of elasticity,hardness（72.9 GPa） and elastic modulus（693.7 GPa） among the samples.Meanwhile,samples fabricated at a low Ar content have higher hardness and modulus.All the results above demonstrate that atmosphere without Ar or low Ar content leads to better mechanical properties of nanodiamond films that are the candidates for applications in MEMS.展开更多
文摘采用微波等离子体化学气相沉积(MPCVD)方法,通过改变CH_4浓度,在单晶Si(100)基底上制备掺氮纳米金刚石(NCD)薄膜,并以所制备的掺氮NCD薄膜为阴极材料,通过场发射扫描电子显微镜(FESEM)、原子力扫描探针显微镜(AFM)、Raman光谱和S波段射频电子枪等测试方法系统地研究了掺氮NCD薄膜的微观结构对微波场发射性能的影响。结果表明:在CH_4浓度(体积比)为4%下,制备的掺氮NCD薄膜的颗粒呈多面体,而且颗粒尺寸和表面粗糙度较大,薄膜中金刚石相含量较高,这些微观结构使得微波场发射性能较高,在电场强度(E_0)为67.7 V·μm^(-1)时,发射电流密度(J0)高达144.8 m A·cm^(-2)。当升高CH_4浓度,所制备的掺氮NCD薄膜的颗粒尺寸减小而且连成条状结构,表面粗糙度也逐渐降低,薄膜中金刚石相减少、非金刚石相增加,这些微观结构的改变使得微波场发射性能逐渐降低。如当CH_4浓度增加至6%时,在电场强度E_0=67.7 V·μm^(-1)时,场发射电流密度降至37.9 m A·cm^(-2)。结果表明:低CH_4浓度下,掺氮NCD薄膜所具有的微观结构有利于微波场发射。
文摘采用微波等离子体化学气相沉积(MPCVD)系统,在单晶硅基底上,以三聚氰胺为氮源实现纳米金刚石(NCD)薄膜N原子掺杂,并通过控制反应气体的压力制备出不同条件的掺氮NCD薄膜。用场发射电子显微镜(FESEM)、原子力探针显微镜(AFM)和激光拉曼光谱(Raman)分析了不同气压对掺氮NCD薄膜表面形貌和物相成分的影响。结果显示:当压力由8 k Pa增加至12 k Pa时,薄膜颗粒尺寸减小,颗粒之间更加致密;表面粗糙度(RMS)也由90.4nm减少至40.4 nm;薄膜中金刚石相逐渐向SP2相转化。继续增加压力至15 k Pa时,薄膜颗粒尺寸呈增加趋势,并且分布不均匀;RMS也增加至131.5 nm;同时薄膜中SP2相含量达到最高。对12 k Pa条件下制备的掺氮NCD薄膜样品进行光电子能谱(XPS)检测,表明薄膜主要以SP2相碳含量为主,并且氮掺杂含量可达2.73%。
基金Projects(51301211,21271188)supported by the National Natural Science Foundation of ChinaProject(2010A0302013)supported by the Foundation of China Academy of Engineering Physics+3 种基金Project(ZZ13005)supported by the Foundation of Laboratory of Ultra Precision Manufacturing Technology of China Academy of Engineering PhysicsProject(2012M521541)supported by the China Postdoctoral Science FoundationProject(20110933K)supported by the State Key Laboratory of Powder Metallurgy,ChinaProject(CSU2013016)support by and the Open-End Fund for Valuable and Precision instruments of Central South University,China
文摘The microscopic mechanical characteristics of ultranano-crystalline diamond films which were prepared in four different atmospheres were investigated for the applications in microelectron-mechanical system（MEMS）.The loading-unloading curves and the change of modulus and hardness of samples along with depth were achieved through nanoindenter.The results show that the films which are made in atmosphere without Ar have the highest recovery of elasticity,hardness（72.9 GPa） and elastic modulus（693.7 GPa） among the samples.Meanwhile,samples fabricated at a low Ar content have higher hardness and modulus.All the results above demonstrate that atmosphere without Ar or low Ar content leads to better mechanical properties of nanodiamond films that are the candidates for applications in MEMS.
