共查询到19条相似文献,搜索用时 125 毫秒
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ZnO/A1lN/Si(111)薄膜的外延生长和性能研究 总被引:3,自引:2,他引:1
用常压金属化学气相沉积法(MOCVD)在Si(111)衬底上制备了马赛克结构ZnO单晶薄膜.引入低温AlN缓冲层以阻止衬底氧化、缓解热失配和晶格失配.薄膜双晶X射线衍射2θ/ω联动扫描只出现了Si(111)、ZnO(000l)及AlN(000l)的衍射峰.ZnO/AlN/Si(111)薄膜C方向晶格常量为0.5195 nm,表明在面方向处于张应力状态;其对称(0002)面和斜对称(1012)面的双晶X射线衍ω摇摆曲线半峰全宽分别为460"和1105";干涉显微镜观察其表面有微裂纹,裂纹密度为20 cm-1;3 μm×3μm范围的原子力显微镜均方根粗糙度为1.5 nm激光实时监测曲线表明薄膜为准二维生长,生长速率4.3μm/h.低温10 K光致发光光谱观察到了薄膜的自由激子、束缚激子发射及它们的声子伴线.所有结果表明,采用金属化学气相沉积法并引入AlN为缓冲层能有效提高Si(111)衬底上ZnO薄膜的质量. 相似文献
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ZnO/AlN/Si(111)薄膜的外延生长和性能研究 总被引:2,自引:0,他引:2
用常压金属化学气相沉积法(MOCVD)在Si(111)衬底上制备了马赛克结构ZnO单晶薄膜。引入低温Al N缓冲层以阻止衬底氧化、缓解热失配和晶格失配。薄膜双晶X射线衍射2θ/ω联动扫描只出现了Si(111)、ZnO(000l)及Al N(000l)的衍射峰。ZnO/Al N/Si(111)薄膜C方向晶格常量为0.5195nm,表明在面方向处于张应力状态;其对称(0002)面和斜对称(1012)面的双晶X射线衍ω摇摆曲线半峰全宽分别为460″和1105″;干涉显微镜观察其表面有微裂纹,裂纹密度为20cm-1;3μm×3μm范围的原子力显微镜均方根粗糙度为1.5nm;激光实时监测曲线表明薄膜为准二维生长,生长速率4.3μm/h。低温10K光致发光光谱观察到了薄膜的自由激子、束缚激子发射及它们的声子伴线。所有结果表明,采用金属化学气相沉积法并引入Al N为缓冲层能有效提高Si(111)衬底上ZnO薄膜的质量。 相似文献
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ZnO外延膜与蓝宝石衬底的取向偏差及其弯曲变形 总被引:1,自引:1,他引:0
采用常压MOCVD方法在Al2O3(00.1)衬底上生长出了高质量ZnO单晶薄膜。由ZnO(00.2)面和Al2O3(00.6)面及ZnO(10.2)面和Al2O3(11.6)面X射线双晶(w/2θ衍射曲线的相对峰位,得到ZnO外延膜的晶格常数及外延层和衬底间的取向差异角。结果表明外延层和衬底在应力作用下产生了取向差和晶格畸变,并且取向倾斜方向与衬底的切割倾角方向一致;高温直接生长的样品的取向差比有低温缓冲层样品更大,晶格畸变也更严重。高温直接生长的样品弯曲半径小而应力更大;实验测量的应力值和理论计算的热应力值之间存在差异,原因主要是晶格失配应力的存在。有缓冲层的样品由于能更好地弛豫晶格失配引入的应力,热应力所占整个残余应力的比例相对更大。 相似文献
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采用有机金属化学气相沉积(MOCVD)在r面蓝宝石衬底上生长a-AlGaN外延膜,研究了AlN插入层对a-AlGaN外延膜的应力和光学性质的影响。根据高分辨X射线衍射(HRXRD)技术和扫描电子显微镜(SEM)我们可以得到,AlN插入层有效地提高了a-AlGaN外延膜的晶体质量并减小了外延膜材料结构的各向异性。由拉曼光谱得到AlN插入层的引入减小了a-AlGaN外延膜的面内压应力,其原因是AlN插入层可以当作衬底有效的调制与减小a-AlGaN外延膜与r面蓝宝石衬底的晶格失配,从而使a-AlGaN的面内应力得到适当释放。对室温下的光致发光进行测量得到AlN插入层的使用使近带边发射峰(NBE)发生了红移,这可能是由于残余应力的减小引起。 相似文献
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利用金属有机化合物气相外延沉积技术在2inch(5.08cm)Si(111)图形衬底上生长了GaN外延薄膜,在Al组分渐变AlGaN缓冲层与GaN成核层之间引入了AlN插入层,研究了AlN插入层对GaN薄膜生长的影响。结果表明,随着AlN插入层厚度的增加,GaN外延膜(002)面与(102)面X射线衍射摇摆曲线半峰全宽明显变小,晶体质量变好,同时外延膜在放置过程中所产生的裂纹密度逐渐减小直至不产生裂纹。原因在于AlN插入层的厚度对GaN成核层的生长模式有明显影响,较厚的AlN插入层使GaN成核层倾向于岛状生长,造成后续生长的nGaN外延膜具有更多的侧向外延成分,从而降低了GaN外延膜中的位错密度,减少了GaN外延膜中的残余张应力。同时还提出了一种利用荧光显微镜观察黄带发光形貌来表征GaN成核层形貌和生长模式的新方法。 相似文献
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采用电子回旋共振等离子体增强金属有机物化学气相沉积(ECR-PEMOCVD)技术,在c轴取向的蓝宝石即α Al2O3(0001)衬底上,以氮化镓(GaN)缓冲层和外延层作为初始层,分别以高纯氮气(N2)和三甲基铝(TMAl)为氮源和铝源低温生长氮化铝(AlN)薄膜.并利用反射高能电子衍射(RHEED)、原子力显微镜(AFM)和x射线衍射(XRD)等测量结果,研究了氢等离子体清洗、氮化和GaN初始层对六方AlN外延层质量的影响,从而获得解理性与α Al2O3衬底一致的六方相AlN单晶薄膜,其XRD半高宽为1
关键词:
AlN
氢等离子体清洗
氮化
GaN 相似文献
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The effect of Al incorporation on the AlGaN growth by metalorganic chemical vapor deposition is investigated. With the increase of trimethylalluminum (TMAl) flux, the crystal quality becomes worse, and the epilayer surface becomes rougher. An interesting phenomenon is that the growth rate of AlGaN decrease with increasing TMAl flux, which is opposite to the AlN growth rate dependence on the TMAl flux. All these effects are attributed to the different properties of Al atoms due to the higher bond strength of Al-N compared with Ga-N, which lead to lower surface mobility and stronger competitive ability of Al atoms during the growth. The enhancement of the surface mobility of Al is especially important for improving the quality of AlGaN. 相似文献
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Influence of Al Preflow Time on Surface Morphology and Quality of AlN and GaN on Si(111) Grown by MOCVD
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《中国物理快报》2017,(5)
We investigate the influence of Al preflow time on surface morphology and quality of AIN and GaN. The AIN and GaN layers are grown on a Si(111) substrate by metal organic chemical vapor deposition. Scanning electron microscopy, atomic force microscopy, x-ray diffraction and optical microscopy are used for analysis. Consequently,we find significant differences in the epitaxial properties of AIN buffer and the GaN layer, which are dependent on the Al preflow time. Al preflow layers act as nucleation sites in the case of AIN growth. Compact and uniform AIN nucleation sites are observed with optimizing Al preflow at an early nucleation stage, which will lead to a smooth AIN surface. Trenches and AIN grain clusters appear on the AIN surface while melt-back etching occurs on the GaN surface with excessive Al preflow. The GaN quality variation keeps a similar trend with the AIN quality, which is influenced by Al preflow. With an optimized duration of Al preflow, crystal quality and surface morphology of AIN and GaN could be improved. 相似文献
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C.H. Chiang K.M. ChenY.H. Wu Y.S. YehW.I. Lee J.F. ChenK.L. Lin Y.L. HsiaoW.C. Huang E.Y. Chang 《Applied Surface Science》2011,257(7):2415-2418
Mirror-like and pit-free non-polar a-plane (1 1 −2 0) GaN films are grown on r-plane (1 −1 0 2) sapphire substrates using metalorganic chemical vapor deposition (MOCVD) with multilayer high-low-high temperature AlN buffer layers. The buffer layer structure and film quality are essential to the growth of a flat, crack-free and pit-free a-plane GaN film. The multilayer AlN buffer structure includes a thin low-temperature-deposited AlN (LT-AlN) layer inserted into the high-temperature-deposited AlN (HT-AlN) layer. The results demonstrate that the multilayer AlN buffer structure can improve the surface morphology of the upper a-plane GaN film. The grown multilayer AlN buffer structure reduced the tensile stress on the AlN buffer layers and increased the compressive stress on the a-plane GaN film. The multilayer AlN buffer structure markedly improves the surface morphology of the a-plane GaN film, as revealed by scanning electron microscopy. The effects of various growth V/III ratios was investigated to obtain a-plane GaN films with better surface morphology. The mean roughness of the surface was 1.02 nm, as revealed by atomic force microscopy. Accordingly, the multilayer AlN buffer structure improves the surface morphology and facilitates the complete coalescence of the a-plane GaN layer. 相似文献
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《Journal of Physics and Chemistry of Solids》2007,68(5-6):1131-1134
AlN growth was performed on c-plane sapphire substrates by metalorganic vapor phase epitaxy (MOVPE) using trimethylaluminium (TMAl) and ammonia. The influence of the carrier gases H2 and N2 and their mixtures on the surface morphology and structural characteristics was investigated as well as the influence of the growth temperature of the total source partial pressure and of the TMAl substrate pretreatment. It was found that smoother layers and better structural characteristics are obtained for lower source partial pressures. Decreasing of growth temperature led to improvement of surface morphology, and increasing of nitrogen in gas phase led to improvement structural quality of the layer. A pretreatment of the substrate leads to rougher layers. 相似文献
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We investigate effects of nitridation on AlN morphology, structural properties and stress. It is found that 3min nitridation can prominently improve AlN crystal structure, and slightly smooth the surface morphology. However, 10min nitridation degrades out-of-plane crystal structure and surface morphology instead. Additionally, 3-min nitridation introduces more tensile stress (1.5 GPa) in AlN films, which can be attributed to the weaker islands 2D coalescent. Nitridation for lOmin can introduce more defects, or even forms polycrystallinity interlayer, which relaxes the stress. Thus, the stress in AlN with 10 min nitridation decreases to -0.2 GPa compressive stress. 相似文献
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采用直流磁控反应溅射法,在Si(111)基底上成功制备了多晶六方相AlN薄膜.研究了溅射过程中溅射气压对薄膜结构和表面粗糙度的影响.结果表明:当溅射气压低于0.6 Pa时,薄膜为非晶态,在傅里叶变换红外光谱中,没有明显的吸收峰;当溅射气压不低于0.6 Pa时,薄膜的X射线衍射图中均出现了六方相的AlN(100)、(11... 相似文献
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Jiafan Chen 《中国物理 B》2022,31(7):76802-076802
We report the growth of porous AlN films on C-face SiC substrates by hydride vapor phase epitaxy (HVPE). The influences of growth condition on surface morphology, residual strain and crystalline quality of AlN films have been investigated. With the increase of the V/III ratio, the growth mode of AlN grown on C-face 6H-SiC substrates changes from step-flow to pit-hole morphology. Atomic force microscopy (AFM), scanning electron microscopy (SEM) and Raman analysis show that cracks appear due to tensile stress in the films with the lowest V/III ratio and the highest V/III ratio with a thickness of about 3 μm. In contrast, under the medium V/III ratio growth condition, the porous film can be obtained. Even when the thickness of the porous AlN film is further increased to 8 μm, the film remains porous and crack-free, and the crystal quality is improved. 相似文献
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研究了直流磁控溅射法沉积AlN薄膜过程中氮气含量对AlN薄膜结构及性能的影响.实验结果表明:当真空腔的氩气含量较低时,薄膜呈非晶态,在红外波段的傅里叶变换光谱中没有明显的吸收峰,当氮气流量为75%时薄膜中出现明显的六方AlN(100)和AlN(110)衍射峰,在波数为670~700cm-1处有强烈的吸收峰;增加氮气含量,薄膜又呈现出非晶状态.薄膜的表面粗糙度和颗粒大小都随氮气含量的增加先增大后减小.. 相似文献
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Two-layered aluminium nitride (AlN)/silicon nitride microbridges were fabricated for microbridge tests to evaluate the elastic modulus, residual stress and tensile strength of the AlN films. The silicon nitride layer was added to increase the robustness of the structure. In a microbridge test, load was applied to the centre of a microbridge and was gradually increased by a nano-indenter equipped with a wedge tip until the sample was broken, while displacement was recorded coherently. Measurements were performed on single-layered silicon nitride microbridges and two-layered AlN/silicon nitride microbridges respectively. The data were fitted to a theory to derive the elastic modulus, residual stress and tensile strength of the silicon nitride films and AlN films. For the AlN films, the three parameters were determined to be 200, 0.06 and 0.3?GPa, respectively. The values of elastic modulus obtained were consistent with those measured by conventional nano-indentation method. The tensile strength value can be used as a reference to reflect the maximum tolerable tensile stress of AlN films when they are used in micro-electromechanical devices. 相似文献