共查询到18条相似文献,搜索用时 171 毫秒
1.
热阴极DC-PCVD方法制备的金刚石厚膜的生长特性和内应力 总被引:8,自引:5,他引:3
采用热阴极DC PCVD(DirectCurrentPlasmaChemicalVaporDeposition)方法制备出大尺寸高质量的金刚石厚膜,研究了金刚石厚膜的生长特性和内应力状态。由热阴极DC PCVD方法制备的金刚石厚膜大多数为〈110〉取向,表面显露面主要是(100)面和(111)面,厚膜的表面被较多的孪晶所覆盖,部分(111)面退化为3个相互垂直的(110)面,孪晶使厚膜表面结晶特性复杂化,金刚石厚膜的晶粒沿生长方向呈现柱状生长。金刚石厚膜的生长速率随甲烷流量和工作气压的增加而增加,但随生长速率的提高金刚石膜的品质明显下降。金刚石厚膜的内应力以压应力为主,随着甲烷浓度的增加压应力增加,随着工作气压的增加压应力减小,到某个气压之后变为张应力。 相似文献
2.
甲烷浓度对CVD金刚石薄膜晶体学生长过程的影响 总被引:2,自引:0,他引:2
采用X射线衍射技术、电子背散射衍射技术和扫描电镜分别观察了不同甲烷浓度条件下沉积的CVD自支撑金刚石薄膜的宏观织构、微区晶界分布和表面形貌.研究了金刚石晶体{100}面和{111}面生长的晶体学过程.研究表明,{100}面通过吸附活性基团CH^2- 2,而{111}面通过交替吸附活性基团CH^-3和CH^-3后脱氢堆积碳原子.低甲烷浓度时,{111}面表面能低于{100}面,使{111}面生长略快于{100}面.甲烷浓度升高,动力学作用增强使{100}面生长明显快于{111}面,使金刚石薄膜产生{100}纤维织构;同时显露的{100}面平行于薄膜表面,竞争生长使位于晶体侧面的{111}面由于相互覆盖而减小,形成了不同于单晶体自由生长的薄膜表面形貌组织. 相似文献
3.
在微波等离子体化学气相沉积装置中 ,采用正交试验法研究金刚石在镜面抛光的Si( 1 0 0 )面上的偏压形核过程中 ,形核时间、偏压电压、气压及甲烷浓度对形核密度的影响 ,研究结果表明 :形核密度随形核时间的增加而增加 ,适中的偏压电压和沉积气压有利于金刚石的形核 ,而甲烷浓度的影响很小。正交试验所得的最佳形核条件为偏压 -1 5 0V ;时间 1 2min ;气压 4kPa;CH4 比率 5 % ,在该条件下金刚石的形核密度达到 1 0 1 0 个 cm2 。 相似文献
4.
5.
《真空科学与技术学报》2016,(5)
利用微波等离子体化学气相沉积(MPCVD)法,在天然金刚石衬底的(111)晶面上同质外延生长单晶金刚石,研究了沉积温度、CH_4浓度以及小角度偏离(111)晶面的衬底对金刚石生长的影响。采用SEM和Raman对外延生长的金刚石进行表征,结果表明:高沉积温度、高CH_4浓度条件下,金刚石呈现出无序的多晶生长现象,随着沉积温度的降低,形貌和质量明显提高,在低沉积温度条件下金刚石表现出一致的单晶生长,但是表面形貌较为粗糙。进一步降低CH_4浓度可外延生长质量高、表面平整的单晶金刚石,速率达4.7μm/h.使用倾斜抛光方法将部分衬底面偏离(111)晶面约6°,对比实验发现,微小偏离(111)晶面的斜面衬底在高沉积温度、高CH_4浓度条件下也能生长出质量较好的单晶金刚石,生长速率明显提高,达到了9μm/h。 相似文献
6.
7.
钢渗铬沉积金刚石膜的研究 总被引:2,自引:0,他引:2
用热解CVD装置研究了甲烷浓度、基底温度、室压对钢渗铬沉积金刚石膜的影响.结果表明,甲烷浓度越低,沉积得到的金刚石膜的晶形越好,甲烷浓度超过0.8%后,金刚石的形貌呈"菜花状";基体温度高时,难于在渗铬层上形成连续的金刚石膜,但基体温度高所得的晶形较好;室压越高,金刚石的形核密度越高,但随室压的升高,金刚石的形貌变差.菜花状金刚石膜是由大量二次晶核长大的微晶金刚石晶粒组成,含有较多的非金刚石碳相. 相似文献
8.
《新型炭材料》2017,(1)
利用微波等离子体化学气相沉积(MPCVD)法在高温高压(HPHT)下制备的单晶片上进行单晶金刚石同质外延生长,研究了甲烷浓度和衬底温度对金刚石生长的影响。利用扫描电子显微镜与激光拉曼光谱仪对生长前后的样品进行表征。结果表明,利用HPHT单晶片上生长时,主要为层状生长和丘状生长模式,丘状生长易出现多晶结构。降低甲烷浓度能够降低丘状生长密度,提高金刚石表面平整度;金刚石生长速率随甲烷浓度、工作气压和衬底温度的增加而提高,但过高的甲烷浓度(72%)和衬底温度(1 150℃)会降低金刚石的质量。所生长出的单晶金刚石质量较为理想,衬底与生长层之间过渡比较自然,金刚石结晶度高,缺陷密度小,但随膜层增厚,非晶碳含量有所增加。 相似文献
9.
本文第1部分评述了低压气相合成金刚石的进展。第2部分介绍了用表面分析方法和HREM对金刚石(111)和(100)面的生长机理,原子氢和氧对金刚石生长本身的影响,亚稳态条件下金刚石的晶形显露规律,硅衬底上的形核机理和初期生长规律进行研究所取得的重要进展。 相似文献
10.
本文研究了微波等离子体化学气相沉积制备金刚石薄膜的宏观控制参量对成核和生 长过程的影响.过高的碳源浓度、低的衬底温度不利于金刚石膜的生长.在金刚石膜的 成核和生长期采用不同的条件,生长出晶形较好的金刚石薄膜。 相似文献
11.
CVD金刚石薄膜(111)与(100)取向生长的热力学分析 总被引:1,自引:0,他引:1
用非平衡热力学耦合模型计算了CVD金刚石薄膜生长过程中C2H2与CH3浓度之比[C2H2]/[CH3]随衬底温度和CH4浓度的变化关系,从理论上探讨了金刚石薄膜(111)面和(100)面取向生长与淀积条件的关系。在衬底温度和CH4浓度由低到高的变化过程中,[C2H2]/[CH3]逐渐升高,导致金刚石薄膜的形貌从(111)晶面转为(100)晶面。添加氧后C2H2与CH3浓度都将下降,但C2H2下降得更多,因而添加氧也使[C2H2]/[CH3]下降,从而有利于生长(111)晶面的金刚石薄膜。 相似文献
12.
Tsao-Ming Hong Sheng-Hsiung Chen Yih-Song Chiou Chia-Fu Chen 《Thin solid films》1995,270(1-2):148-153
The influence of nitrogen on the growth of diamond using unconventional gas mixtures of CH4---CO2 by microwave plasma chemical vapor deposition was investigated. A clear improvement in the surface morphology and quality of the diamond films indicates the beneficial effect of adding nitrogen to CH4-CO2 gas mixtures. However, most interestingly, for lower methane concentration, the addition of small amounts of nitrogen resulted in the formation of isolated diamond particles possessing a vacant “cage-like” structure with completed {100} facets This result indicates that the continued addition of nitrogen gives rise to the deterioration of {111} facets and the retention of {100} facets. Analysis using Auger electron spectroscopy and secondary ion mass spectroscopy shows very low and uniform levels of nitrogen in the diamond films. Although the amount of atomic hydrogen in the ground state decreased and CN radicals increased with increasing amounts of added nitrogen, good-quality diamond films were deposited resulting from a larger amount of atomic oxygen and the decrease in the C2 emissions in the gas phase under optimum conditions. 相似文献
13.
In this work, we report {100} multi-faceted diamond from large grained micro- to nano-crystalline obtained by microwave plasma chemical vapor deposition (MPCVD). The diamond samples were grown using different microwave power 2000 and 3200 W with a small amount of nitrogen and oxygen addition into conventional methane and hydrogen plasma in a 5 kW MPCVD reactor. Scanning electron microscopy (SEM), micro-Raman spectroscopy and X-ray diffraction (XRD) were used to characterize the morphology, crystalline quality and orientation or texture of the diamond samples. SEM micrographs clearly evidence various diamonds of distinct morphologies consisting of smooth square {100} facets from micrometer or nanometer size. Especially novel morphology, large {100} faceted nanocrystalline diamond balls of high growth rate 17.0 μm/h were obtained. The effect of microwave power and temperature and the role of nitrogen addition on diamond growth rate and the formation of different types of {100} faceted diamond from micro- to nanocrystalline is discussed. These results shed light into the specific growth mechanism of CVD diamond upon nitrogen perturbation. 相似文献
14.
The hydrogenation of Ib-type single crystalline diamond with grain size of several tens of micrometers, synthesized by high-pressure and high-temperature (HPHT) sintering, was carried out by hydrogen plasma treatment in a hot-filament chemical vapor deposition (HFCVD) system. After exposure to air, the surface conductivity of (001) and (111) facets of HPHT single crystalline diamond was measured. The influences of hydrogenation duration, temperature and gas pressure on the surface conductivity of (001) and (111) facets have been investigated. The measurement results show that the variation of hydrogenation conditions has a noticeable effect on the surface conductivity of single crystalline diamond, which is closely related to the formation of a chemical vapor deposition (CVD) regrowth layer on the facets induced by hydrogen plasma treatment process. In addition, (001) surface exhibits higher electrical conductivity than (111) surface, which is mainly attributed to less nitrogen concentration on the (001) surface than on the (111) surface. 相似文献
15.
16.
Mahtab Ullah Ejaz Ahmed Abdelbary Elhissi Waqar Ahmed 《Bulletin of Materials Science》2014,37(3):579-583
Polycrystalline diamond thin films with outgrowing diamond (OGD) grains were deposited onto silicon wafers using a hydrocarbon gas (CH4) highly diluted with H2 at low pressure in a hot filament chemical vapour deposition (HFCVD) reactor with a range of gas flow rates. X-ray diffraction (XRD) and SEM showed polycrystalline diamond structure with a random orientation. Polycrystalline diamond films with various textures were grown and (111) facets were dominant with sharp grain boundaries. Outgrowth was observed in flowerish character at high gas flow rates. Isolated single crystals with little openings appeared at various stages at low gas flow rates. Thus, changing gas flow rates had a beneficial influence on the grain size, growth rate and electrical resistivity. CVD diamond films gave an excellent performance for medium film thickness with relatively low electrical resistivity and making them potentially useful in many industrial applications. 相似文献
17.
The evolution of grain size, grain-size distribution, morphological and crystallographic texture, surface roughness, and the contribution of various surface facets to the growth of polycrystalline diamond films is performed by carrying out a series of two-dimensional computer simulations. The films are assumed to grow from a set of randomly oriented, {100}- and {111}-faceted nuclei by the motion of their vertices (the points where the adjoining facets of the same or neighboring grains meet). The vertex velocities are found to be a function of the orientation and the growth rate of the adjoining facets. To quantify the latter, a {100} to {111} growth-rate parameter is used. The results show that the evolution of the grain size and its distribution, surface roughness, morphological and crystallographic texture, and the portion of the film grown from different surface facets are all mutually linked and governed by the magnitude of the growth-rate parameter. The latter can be controlled by the CVD processing conditions, such as the substrate temperature, reactor pressure, mole fraction of carbon-source gas (e.g., CH4, C2H2). 相似文献
18.
用微波等离子体化学气相沉积法(MPCVD)在氧化铝陶瓷衬底上成功地制备出具有[100]织构的金刚石薄膜,并对该薄膜进行了X射线衍射(XRD)、扫描电子显微镜(SEM)和Raman光谱分析。由于氦原子具有高的电离能,因此本工作在反应气氛中引入了少量的氦。以提高氢等离子体的刻蚀效率,实验结果表明,少量氦气的引入促进了等离子体对非(100)面的选择性刻蚀,从而也有利于金刚石薄膜的[100]织构生长。 相似文献