用气相沉积方法在低气压下制备BN的高压相：E-BN、c-BN、w-BN

 用射频磁控溅射方法得到了低应力立方氮化硼薄膜。红外光谱结果表明,薄膜具有很好的附着力,且含有少量的E-BN和w-BN。电子衍射谱表明薄膜表层是纯立方相。同时利用此方法得到了E-BN薄膜。认为在薄膜生长过程中可能经历了一个从E-BN到c-BN的相转变过程。     

金刚石基底上氮化硼薄膜的场发射特性研究

 利用射频磁控溅射方法,在金刚石膜上沉积了氮化硼薄膜。红外光谱分析表明,氮化硼薄膜的结构为六角氮化硼。在超高真空系统中测量了样品的场发射特性,沉积在金刚石膜上的氮化硼薄膜的阈值电场为12 V/μm,最大发射电流密度为272 μA/cm²。并且沉积在金刚石膜上的氮化硼薄膜的场发射特性明显优于金刚石薄膜本身的场发射特性。这说明,氮化硼薄膜可以有效地改善金刚石膜的场发射特性。场发射Fowler-Nordheim（F-N）曲线表明,电子发射是通过遂穿表面势垒完成的。     

等离子体增强脉冲激光沉积o-BN薄膜

利用等离子体增强脉冲激光沉积系统在Si（100）基底上沉积出了高质量的o-BN薄膜,利用红外光谱（FTIR）、X射线衍射谱（XRD）和原子力显微镜照片对o-BN薄膜进行了表征.通过红外光谱（FTIR）得到o-BN薄膜的红外峰特征峰值为1189cm^-1,1585cm^-1和1450cm^-1;由XRD谱得到o-BN薄膜的（111）,（020）,（021）,（310）和（243）各晶面的衍射峰, 特别是（310）和（243）晶面的衍射峰非常强;通过原子力显微镜照片清楚看到BN薄膜具有尖状突起的表面形貌. 关键词： 等离子体增强脉冲激光沉积 氮化硼薄膜 X射线衍射谱     

等离子体化学气相沉积及其在沉积超硬膜方面的应用

本文简要介绍了等离子体化学气相沉积的基本原理和几种主要类型的工艺特点，着重介绍了等离子体化学气相沉积在沉积超硬膜方面的新进展，主要包括制备氮化钛类薄膜、立方氮化硼薄膜、类金刚石薄膜及金刚石薄膜。     

FTIR法研究BCN薄膜的内应力

采用射频磁控溅射技术,用六角氮化硼和石墨为溅射靶,以氩气(Ar)和氮气(N₂)为工作气体,在Si(100)衬底上制备出硼碳氮(BCN)薄膜。利用傅里叶变换红外光谱(FTIR)考察了不同沉积参数(溅射功率为80～130 W、衬底温度为300～500 ℃、沉积时间为1～4 h)条件下制备的薄膜样品。实验结果表明,所制备薄膜均实现了原子级化合。并且沉积参数对BCN薄膜的生长和内应力有很大影响,适当改变沉积参数能有效释放BCN薄膜的内应力。在固定其他条件只改变一个沉积参数的情况下,得到制备具有较小内应力的硼碳氮薄膜的最佳沉积条件：溅射功率为80 W、衬底温度为400 ℃、沉积时间为2 h。     

脉冲直流偏压增强的高质量立方氮化硼薄膜的合成

采用磁增强活性反应离子镀系统成功地合成了立方氮化硼薄膜.通过给基片施加脉冲直流偏压以代替传统的射频偏压,增强了立方氮化硼的成膜稳定性,研究了基片的直流脉冲偏压、等离子体放电电流、通入气体流量比(Ar/N₂)和基片温度沉积参数对立方氮化硼薄膜形成的影响规律.结果表明:随着基片负偏压和放电电流的增大,薄膜中立方氮化硼的纯度提高,当基片负偏压为155V,放电电流为15A时,可获得几乎单相的立方氮化硼薄膜.基片温度为500℃和Ar/N₂流量比为10时,最有利于立方氮化硼 关键词： 立方氮化硼 活性反应离子镀 脉冲偏压     

立方氮化硼单晶-金刚石薄膜异质p-n结

 在Si中掺杂N型片状立方氮化硼单晶的(111)面上,利用热灯丝化学气相沉积方法生长了掺B的p型金刚石薄膜,从而制得了立方氮化硼单晶-金刚石薄膜异质p-n结,测试了该p-n结的V-A特性,结果表明其整流特性良好。     

脉冲高能量密度等离子体薄膜制备与材料表面改性

脉冲高能量密度等离子体是一项全新的等离子体材料表面处理和薄膜制备技术。文章主要介绍了作者近几年来在这方面的研究成果。从理论和试验上研究了脉冲高能量密度等离子体的产生机制及其物理性质，研究了脉冲等离子体与材料相互作用的基本物理现象和物理机制，诊断测量表明，脉冲等离子体具有电子温度高（10－100eV）、等离子体密度高（10^14-10^16cm^-3）、定向速度高（－10^7cm/s）、功率大（10^4W/cm^2）等特点，在制备薄膜时具有沉积速率高，薄膜与基底粘结力强，并兼有激光表面处理、电子束处理、冲击波轰击、离子注入、溅射、化学气相沉积等综合性特点，可以在室温下合成亚稳态相和其他化合物材料。在此基础上，系统地进行了脉冲等离子体薄膜制备和材料表面改性及其机理的研究，在室温下的不同材料衬底上成功的沉积了性能良好的较大颗粒立方氮化硼、碳氮化钛、氮化钛、类金刚石、氮化铝等薄膜材料，沉积薄膜和基底之间存在一个很宽的过渡层，因此导致薄膜与基底有很强的粘结力，经脉冲等离子体处理过的金属材料表面性能得到了极大改善。     

立方氮化硼薄膜的光学带隙

用射频溅射法在p型Si(100)衬底上沉积立方氮化硼(c-BN)薄膜,薄膜的成分由傅里叶变换红外谱标识,用紫外-可见分光光度计测量了c-BN薄膜的反射光谱,利用K-K(Kramers-Kroning)关系从反射谱计算出c-BN薄膜的光吸收系数,进而确定c-BN薄膜的光学带隙.对于立方相含量为55.4%的c-BN薄膜,光学带隙为5.38eV. 关键词： 立方氮化硼薄膜 光学带隙 K-K关系     

衬底材料对制备立方氮化硼薄膜的影响

较系统地研究了不同衬底材料对制备氮化硼薄膜的影响。用热丝增强射频等离子体CVD法,以NH3,B2H6和H2为反应气体,在Si,Ni,Co和不锈钢等衬底材料上,成功生长出高质量的立方氮化硼薄膜,还用13.56MHz的射频溅射系统将c-BN薄膜沉积在Si衬底上,靶材为h-BN(纯度为99.99％）,溅射气体为氩气和氮气的混合气体,所得到的氮化硼薄膜中立方相含量高于90%,用X射线衍射谱和傅里叶变换红谱对样品进行了分析表明,衬底材料与c-BN的晶格匹配情况,对于CVD生长立方氮化硼薄膜影响很大,而对溅射生长立方氮化硼薄膜影响不大。     

Deposition of hexagonal boron nitride thin films on silver nanoparticle substrates and surface enhanced infrared absorption

Silver nanoparticle thin films with different average particle diameters are grown on silicon substrates. Boron nitride thin films are then deposited on the silver nanoparticle interlayers by radio frequency （RF） magnetron sputtering. The boron nitride thin films are characterized by Fourier transform infrared spectra. The average particle diameters of silver nanoparticle thin films are 126.6, 78.4, and 178.8 nm. The results show that the sizes of the silver nanoparticles have effects on the intensities of infrared spectra of boron nitride thin films. An enhanced infrared absorption is detected for boron nitride thin film grown on silver nanoparticle thin film. This result is helpful to study the growth mechanism of boron nitride thin film.     

Surface properties of cubic boron nitride thin films

Studying the surface properties of cubic boron nitride (c-BN) thin films is very important to making it clear that its formation mechanism and application. In this paper, c-BN thin films were deposited on Si substrates by radio frequency sputter. The influence of working gas pressure on the formation of cBN thin film was studied. The surface of c-BN films was analyzed by X-ray photoelectron spectroscopy (XPS), and the results showed that the surface of c-BN thin films contained C and O elements besides B and N. Value of N/B of c-BN thin films that contained cubic phase of boron nitride was very close to 1. The calculation based on XPS showed that the thickness of hexagonal boron nitride (h-BN) on the surface of c-BN films is approximately 0.8 nm.     

立方氮化硼薄膜的最新研究进展

立方氮化硼(cBN)作为一种在自然界中并不存在的人造材料具有优异的理化特性. 在超硬刀具、高温电子器件和光学保护膜等领域有着广泛的应用前景,已经成为材料科学的研究热点之一. 但是气相生长高质量cBN薄膜仍然还有许多难点需要攻克. 在综述近几年cBN薄膜研究所取得的一些突破性进展后,结合研究现状提出今后可能的主要研究方向. 关键词： 立方氮化硼薄膜 压缩应力 异质外延 掺杂     

Influence of oxygen on the growth of cubic boron nitride thin films by plasma-enhanced chemical vapour deposition

Cubic boron nitride thin films were deposited on silicon substrates by low-pressure inductively coupled plasma-enhanced chemical vapour deposition. It was found that the introduction of O₂ into the deposition system suppresses both nucleation and growth of cubic boron nitride. At a B₂H₆ concentration of 2.5\% during film deposition, the critical O₂ concentration allowed for the nucleation of cubic boron nitride was found to be less than 1.4\%, while that for the growth of cubic boron nitride was higher than 2.1\%. Moreover, the infrared absorption peak observed at around 1230--1280~cm^-1, frequently detected for cubic boron nitride films prepared using non-ultrahigh vacuum systems, appears to be due to the absorption of boron oxide, a contaminant formed as a result of the oxygen impurity. Therefore, the existence of trace oxygen contamination in boron nitride films can be evaluated qualitatively by this infrared absorption peak.     

Residual compressive stress and intensity of infrared absorption of cubic BN films prepared by plasma enhanced chemical vapor deposition

Theoretical and experimental investigations on the dependence of the intensity of infrared （IR） absorption of poly- crystalline cubic boron nitride thin films under the residual compressive stress conditions have been performed. Our results indicate that the intensity of the IR absorption is proportional to the total degree of freedom of all the ions in the ordered regions. The reduction of interstitial Ar atom concentration, which causes the increase in the ordered regions of cubic boron nitride （cBN） crystallites, could be one cause for the increase in the intensity of IR absorption after residual compressive stress relaxation. Theoretical derivation is in good agreement with the experimental results concerning the IR absorption intensity and the Ar interstitial atom concentration in cubic boron nitride films measured by energy dispersion X-ray spec- troscopy. Our results also suggest that the interstitial Ar is the origin of residual compressive stress accumulation in plasma enhanced cBN film deposition.     

立方氮化硼薄膜生长过程中的界面控制

在立方氮化硼薄膜气相生长过程中生成的无定形初期层和乱层结构氮化硼中间层，一直是阻碍立方氮化硼薄膜外延生长的主要原因.系统地分析了硅衬底预处理对立方氮化硼薄膜中无定形初期层成分的影响，发现在等离子体化学气相生长法制备薄膜时，硅衬底上形成无定形初期层的可能原因有氧的存在、离子轰击以及高温下硅的氮化物的形成.在H₂气氛中1200K热处理硅衬底可以有效地减少真空室中残留氧浓度，除去硅表面的自然氧化层，保持硅衬底表面晶体结构.控制衬底温度不超过900 K，就能防止硅的氮化物的形成，成功地除去无 关键词： 立方氮化硼薄膜 等离子体化学气相生长 界面 电子显微镜     

无序双层六角氮化硼量子薄膜的电子性质

基于安德森紧束缚模型,本文研究了无序双层六角氮化硼量子薄膜的电子性质. 数值计算结果表明在双层都无序掺杂的情况下,六角氮化硼量子薄膜的电子是局域的, 其表现为绝缘体性质;而对于单层掺杂(无论是氮原子还是硼原子)的双层六角氮化硼量子薄膜, 在能谱的带尾出现了持续的迁移率边.这就说明在单层掺杂的双层六角氮化硼量子薄膜中产生了 金属绝缘体转变.这一结果证实了有序-无序分区掺杂的理论模型,为理解及调控双层六角氮化硼量子薄膜 的电子性质提供了有益的理论指导.     

STRESS ANALYSIS IN CUBIC BORON NITRIDE FILMS BY X-RAY DIFFRACTION USING sin2 ψ METHOD

The boron nitride (BN) films containing cubic boron nitride (c-BN) and hexagonal boron nitride (h-BN) were prepared by radio frequency a ssisted thermal filament chemical vapor deposition. The stress and strain in BN films were investigated by X-ray diffraction analysis using the sin² ψ method. The results showed that both c-BN and h-BN in the same film have similar values of elastic strain, however, the compressive stress in c-BN is much greater than that in h-BN for the same film. Both stress and strain gradually decre ased with the increase of substrate temperature (T_s). The effective stress in the films calculated by the effective stress model increased with the increase of T_s. Furthermore, the dependence of effective stress in the films on T_s was also investigated.     

Spectroscopic in situ diagnostics of boron nitride film growth in plasma-enhanced deposition

The development of in situ diagnostics of the most important species and reactions in the plasma and/or on the surface during thin-film growth is one of the current topics in plasma-enhanced vapor deposition. In situ thin film diagnostic methods which could be used in plasma processing are restricted due to the presence of electrons and ions. The advantages and disadvantages of different applicable methods will be discussed. The spectroscopic in situ control of boron nitride film growth is presented as an example of surface modification in low-temperature, low-pressure plasma processing. The growth of cubic and hexagonal boron nitride is observed by polarized infrared reflection spectroscopy in absorption and ellipsometric configurations as well as by single-wavelength ellipsometry in the visible spectral range. Modeling of the experimental results gives detailed information on growth conditions and internal stress of the films. Received: 8 August 2000 / Accepted: 12 December 2000 / Published online: 3 April 2001