共查询到19条相似文献,搜索用时 203 毫秒
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采用自制的立式HVPE设备,在GaN/蓝宝石复合衬底上生长了GaN厚外延膜,利用AFM,SEM,XRD,RBS/Channeling,CL,PL以及XPS等技术分析了厚膜的结构和光学性能.结果表明,外延层表面具有台阶结构,接近以层流生长方式二维生长,一些六角形的坑出现在膜表面,坑区具有很强的发光.腐蚀试验显示EPD仅8×106 cm-2;XRD和RBS/channeling表明GaN膜具有较好的晶体质量;PL结果也证明外延层具有高的质量,出现了尖锐的带边峰,半高宽仅67meV,同时出现了黄带和红外带,这些带的出现可能是由本征缺陷和C,O等杂质引起的. 相似文献
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为了得到高质量的GaN材料,首先在c面蓝宝石(Al2O3)衬底上射频磁控溅射不同厚度的ZnO缓冲层,然后采用氢化物气相外延(HVPE)法在ZnO缓冲层上生长约5.2μm厚的GaN外延层,研究ZnO缓冲层的厚度对GaN外延层质量的影响。用微分干涉显微镜(DIC)、扫描电子显微镜(SEM)、X射线衍射(XRD)和光致发光(PL)技术研究分析了GaN外延层的表面形貌、结晶质量和光学特性。结果表明,ZnO缓冲层的厚度对GaN外延层的特性有着重要的影响,200 nm厚的ZnO缓冲层最有利于高质量GaN外延层的生长。 相似文献
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GaN在Si(001)上的ECR等离子体增强MOCVD直接生长研究 总被引:3,自引:0,他引:3
研究了用电子回旋共振(ECR)等离子体增强金属有机物化学气相沉积(PEMOCVD)技术在Si(001)衬底上,低温(620~720℃)下GaN薄膜的直接外延生长及晶相结构.高分辨透射电镜(HRTEM)和X射线衍射(XRD)结果表明:在Si(001)衬底上外延出了高度c轴取向纤锌矿结构的GaN膜,但在GaN/Si(001)界面处自然形成了一层非晶层,其两个表面平坦而陡峭,厚度均匀(≈2nm).分析认为,在初始成核阶段N与Si之间反应所产生的这层SixNy非晶层使GaN的β相没有形成.XRD和原子力显微镜(AFM)结果表明,衬底表面的原位氢等离子体清洗,GaN初始成核及后续生长条件对GaN膜的晶体质量非常重要. 相似文献
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研究了用电子回旋共振(ECR)等离子体增强金属有机物化学气相沉积(PEMOCVD)技术在Si(001)衬底上,低温(620~720℃)下GaN薄膜的直接外延生长及晶相结构.高分辨透射电镜(HRTEM)和X射线衍射(XRD)结果表明:在Si(001)衬底上外延出了高度c轴取向纤锌矿结构的GaN膜,但在GaN/Si(001)界面处自然形成了一层非晶层,其两个表面平坦而陡峭,厚度均匀(≈2nm).分析认为,在初始成核阶段N与Si之间反应所产生的这层SixNy非晶层使GaN的β相没有形成.XRD和原子力显微镜(AFM)结果表明,衬底表面的原位氢等离子体清洗,GaN初始成核及后续生长条件对GaN膜的晶体质量非常重要. 相似文献
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T.B. Wei R.F. Duan J.X. Wang J.M. Li Z.Q. Huo Y.P. Zeng 《Microelectronics Journal》2008,39(12):1556-1559
A GaN film with a thickness of 250 μm was grown on a GaN/sapphire template in a vertical hydride vapor phase epitaxy (HVPE) reactor. The full-width at half-maximum (FWHM) values of the film were 141 and 498 arcsec for the (0 0 2) and (1 0 2) reflections, respectively. A sharp band-edge emission with a FWHM of 20 meV at 50 K was observed, which corresponded to good crystalline quality of the film. Some almost circular-shaped hillocks located in the spiral growth center were found on the film surface with dimensions of 100 μm, whose origin was related to screw dislocations and micropipes. Meanwhile, large hexagonal pits also appeared on the film surface, which had six triangular {1 0 1} facets. The strong emission in the pits was dominated by an impurity-related emission at 377 nm, which could have been a high-concentration oxygen impurity. 相似文献
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额外HCl和氮化对HVPE GaN生长的影响 总被引:2,自引:0,他引:2
在氢化物气相外延(HVPE)生长Ga N过程中,发现了一种在成核阶段向生长区添加额外HCl来改善Ga N外延薄膜质量的方法,并且讨论了额外HCl和氮化对Ga N形貌和质量的影响.两种方法都可以大幅度地改善Ga N的晶体质量和性质,但机理不同.氮化是通过在衬底表面形成Al N小岛,促进了衬底表面的成核和薄膜的融合;而添加额外HCl则被认为是通过改变生长表面的过饱和度引起快速成核从而促进薄膜的生长而改善晶体质量和性质的 相似文献
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J. W. P. Hsu M. J. Manfra D. V. Lang K. W. Baldwin L. N. Pfeiffer R. J. Molnar 《Journal of Electronic Materials》2001,30(3):110-114
Scanning force microscopy was used to examine the surfaces of AlGaN/GaN heterostructures grown by molecular beam epitaxy (MBE)
on GaN templates prepared by hydride vapor phase epitaxy (HVPE). Away from dislocations, the MBE growth replicates the surface
morphology of the HVPE film, with monolayer steps clarly visible in topographic images. However, the surface morphology near
dislocations depends strongly on the MBE growth conditions. Under Ga rich growth the dislocations appear as hillocks, while
under stoichiometric growth they appear as pits. A dependence on Al concentration is also observed. Surface contact potential
variation near dislocations is consistent with excess negative charges surrounding by a depletion region, but this was observed
only for the film grown under stoichiometric conditions. 相似文献
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氢化物气相外延(HVPE)法具有生长成本低、生长条件温和、生长速率快等优点,被认为是生长高质量GaN单晶衬底的最有潜力的方法。为了优化HVPE生长GaN的条件,通过改变NH3流量调控Ⅴ/Ⅲ比(NH3流量与HCl流量之比)。通过建立简单的生长模型,对不同Ⅴ/Ⅲ比下GaN薄膜形态变化的机理进行了分析,研究了HVPE生长过程中氮源(Ⅴ族)和镓源(Ⅲ族)不同流量比对结晶质量和表面形貌的影响。实验结果表明,低Ⅴ/Ⅲ比会导致成核密度低,岛状晶胞难以合并;高Ⅴ/Ⅲ比会降低表面Ga原子的迁移率,导致表面高度差异大,结晶质量差。与Ⅴ/Ⅲ比为15.000和28.125相比,Ⅴ/Ⅲ比为21.250时更适合GaN薄膜生长,得到的晶体质量最高。 相似文献
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A. E. Nikolaev S. V. Rendakova I. P. Nikitina K. V. Vassilevski V. A. Dmitriev 《Journal of Electronic Materials》1998,27(4):288-291
6H-SiC/GaN pn-heterostructures were grown by subsequent epitaxial growth of p-SiC by low temperature liquid phase epitaxy
(LTLPE) and n-GaN by hydride vapor phase epitaxy (HVPE). For the first time, p-type epitaxial layers grown on 6H-SiC wafers
were used as substrates for GaN HVPE growth. The GaN layers exhibit high crystal quality which was determined by x-ray diffraction.
The full width at a half maximum (FWHM) for the ω-scan rocking curve for (0002) GaN reflection was ∼120 arcsec. The photoluminescence
spectra for these films were dominated by band-edge emission. The FWHM of the edge PL peak at 361 nm was about 5 nm (80K). 相似文献
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GaN薄膜异质外延制备技术的进展 总被引:2,自引:0,他引:2
介绍了采用MOCVD或HVPE技术高质量异质外延生长GaN薄膜的发展状况。分析和比较了以不同材料为衬底或过渡层生长GaN的工艺过程和薄膜质量,对生长动力学机理也作了简要介绍。 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,在康宁7101型普通玻璃衬底上沉积了高度c轴择优取向的多晶GaN薄膜. 利用反射高能电子衍射(RHEED) , X射线衍射 (XRD) 对样品进行检测,研究了在低温(430℃)沉积中氮气流量对GaN薄膜结晶性的影响. 并且利用原子力显微镜 (AFM) 和室温光致发光 (PL) 谱研究了薄膜的表面形貌和发光特性,发现薄膜表面形貌较为平整,其发光峰由较强的紫外近带边发光峰和极其微弱的绿光发光峰组成. 相似文献