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1.
GaN薄膜生长实时监控系统的实现 总被引:1,自引:0,他引:1
分析了在ECR-MOCVD装置上外延生长GaN单晶薄膜的工艺过程特点和在此过程中影响GaN结晶质量的主要因素.在此基础上,设计了一套监控系统,用于GaN外延生长的工艺流程监控,并提出了一种合适的工艺流程监控策略. 相似文献
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文章分析了在ECR-MOCVD装置上外延生长GaN单晶薄膜的工艺过程特点和在此过程中影响GaN结晶质量的主要因素,在此基础上,设计了一套由80C31单片机为核心的光电隔离电路和PC机组成的两级系统,用于GaN薄膜外延生长的工艺流程监控,并提出了一种合适的工艺流程监控策略。 相似文献
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使用分子束外延方法,采用In束流保护下的调制中断生长技术,在(0001)蓝宝石衬底上生长GaN薄膜.利用反射式高能电子衍射(RHEED)对生长进行实时监控,并用扫描电子显微镜(SEM)、原子力显微镜(AFM)和X射线衍射(XRD)法对GaN外延薄膜的表面形貌和晶体质量进行分析.实验结果表明:采用该技术生长的Ga极性GaN外延薄膜中的晶体表面残留Ga滴密度大大降低,GaN外延薄膜的表面形貌得到改善,其均方根粗糙度(RMS)由3nm降低为0.6nm,同时XRD双晶摇摆曲线测试的结果表明,GaN外延层的晶格质量也得到改善. 相似文献
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使用分子束外延方法,采用In束流保护下的调制中断生长技术,在(0001)蓝宝石衬底上生长GaN薄膜.利用反射式高能电子衍射(RHEED)对生长进行实时监控,并用扫描电子显微镜(SEM)、原子力显微镜(AFM)和X射线衍射(XRD)法对GaN外延薄膜的表面形貌和晶体质量进行分析.实验结果表明:采用该技术生长的Ga极性GaN外延薄膜中的晶体表面残留Ga滴密度大大降低,GaN外延薄膜的表面形貌得到改善,其均方根粗糙度(RMS)由3nm降低为0.6nm,同时XRD双晶摇摆曲线测试的结果表明,GaN外延层的晶格质量也得到改善. 相似文献
5.
在Si(111)衬底上采用金属有机化合物化学气相沉积(MOCVD)技术外延生长GaN薄膜,对外延生长所得GaN薄膜的晶体结构和表面形貌进行表征,并研究SiNx插入层对GaN薄膜的晶体质量和表面形貌的影响.结果表明,在Si衬底上生长GaN薄膜过程中引入SiNx插入层可使GaN薄膜的(10-12)面的X-射线回摆曲线的半峰宽(FWHM)值从974.01减小到602.01arcsec;表面凹坑等缺陷减少、表面平整度提高.可见,SiNx插入层对在Si衬底上外延生长GaN薄膜的晶体质量和表面形貌有着重要的影响. 相似文献
6.
采用在AlN缓冲层后原位沉积SiN掩膜层,然后横向外延生长GaN薄膜.通过该法在硅衬底上获得了1.7 μm无裂纹的GaN薄膜,并在此基础上外延生长出了GaN基发光二极管(LED)外延片,其外延片的总厚度约为1.9 μm.采用高分辨率双晶X-射线衍射(DCXRD)、原子力显微镜(AFM)测试分析.结果表明,GaN薄膜(0002)面的半峰全宽(FWHM)降低到403 arcsec,其表面平整度得到了很大的改善;InGaN/GaN多量子阱的界面较平整,结晶质量良好.光致发光谱表明,GaN基LED峰值波长为469.2 nm. 相似文献
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采用条形Al掩模在Si(111)衬底上进行了GaN薄膜侧向外延的研究.结果显示,当掩模条垂直于Si衬底[11-2]方向,也即GaN[10-10]方向时,GaN无法通过侧向生长合并得到表面平整的薄膜;当掩模条平行于Si衬底[11-2]方向,也即GaN[10-10]方向时,GaN侧向外延速度较快,有利于合并得到平整的薄膜.同时,研究表明,升高温度和降低生长气压都有利于侧向生长.通过优化生长工艺,在条形Al掩模Si(111)衬底上得到了连续完整的GaN薄膜.原子力显微镜测试显示,窗口区域生长的GaN薄膜位错密度约为1×109/cm2,而侧向生长的GaN薄膜位错密度降低到了5×107/cm2以下. 相似文献
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采用氢化物气相外延(HVPE)方法在2英寸(1英寸=2.54 cm)c面蓝宝石衬底上外延生长了高质量GaN单晶薄膜.在GaN生长过程中引入点状和条状两种金属Ti掩膜图形层,研究了不同Ti掩膜图形层对外延生长GaN薄膜晶体质量的影响.使用微分干涉相差显微镜(DICM)、扫描电子显微镜(SEM)、阴极荧光光谱(CL)、喇曼光谱和X射线衍射(XRD)对制备的GaN样品结构和形貌进行了表征分析.实验结果表明,Ti掩膜图形层的引入可以在一定程度上改善GaN薄膜的表面形貌,缓解材料中的应力,降低GaN材料中的位错密度,提高材料的结晶质量.同时发现,相比于点状图形,条状Ti图形掩膜层可以更加有效地改善GaN材料的晶体质量,将位错密度降低到3.2×106 cm-2以下. 相似文献
11.
本文研究了在Si(111)衬底上生长GaN外延层的方法。相比于直接在AlN缓冲层上生长GaN外延层,引入GaN过渡层显著地提高了外延层的晶体质量并降低了外延层的裂纹密度。使用X射线双晶衍射仪、光学显微镜以及在位监测曲线分析了GaN过渡层对外延层的晶体质量以及裂纹密度的影响。实验发现,直接在AlN缓冲层上生长外延层,晶体质量较差, X射线(0002)面半高宽最优值为0.686°,引入GaN过渡层后,通过调整生长条件,控制岛的长大与合并的过程,从而控制三维生长到二维生长过渡的过程,外延层的晶体质量明显提高, (0002)面半高宽降低为0.206°,并且裂纹明显减少。研究结果证明,通过生长合适厚度的GaN过渡层,可以得到高质量、无裂纹的GaN外延层。 相似文献
12.
The impact of nitridation and nucleation layer process conditions on morphology and electron transport in GaN epitaxial films 总被引:1,自引:0,他引:1
A. E. Wickenden D. D. Koleske R. L. Henry R. J. Gorman J. C. Culbertson M. E. Twigg 《Journal of Electronic Materials》1999,28(3):301-307
A systematic study has been performed to determine the characteristics of an optimized nucleation layer for GaN growth on
sapphire. The films were grown during GaN process development in a vertical close-spaced showerhead metalorganic chemical
vapor deposition reactor. The relationship between growth process parameters and the resultant properties of low temperature
GaN nucleation layers and high temperature epitaxial GaN films is detailed. In particular, we discuss the combined influence
of nitridation conditions, V/III ratio, temperature and pressure on optimized nucleation layer formation required to achieve
reproducible high mobility GaN epitaxy in this reactor geometry. Atomic force microscopy and transmission electron microscopy
have been used to study improvements in grain size and orientation of initial epitaxial film growth as a function of varied
nitridation and nucleation layer process parameters. Improvements in film morphology and structure are directly related to
Hall transport measurements of silicon-doped GaN films. Reproducible growth of silicon-doped GaN films having mobilities of
550 cm2/Vs with electron concentrations of 3 × 1017 cm−3, and defect densities less than 108 cm−2 is reported. These represent the best reported results to date for GaN growth using a standard two-step process in this reactor
geometry. 相似文献
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LIAO Xiu-ying ZHU Yan-ling YANG Xiao-bo ZHAO Hong ZHAO Wen-bo ZHOU Xun ZOU Ze-ya ZENG Qing-gao 《半导体光子学与技术》2008,14(4):224-228
The crystal quality of p-GaN film depends on the stress-strain during the process of material growth at a certain extent. A smooth high-quality GaN epitaxial layer was grown on sapphire substrate using standard low-temperature(LT) buffer layer by MOCVD. And by testing analysis of correlative experiments, we found that the stress-strain of p-type GaN could be changed by annealing, enhancing the crystal quality. 相似文献
15.
R. Quay Dipl.-Phys. Dr. techn. G. Weimann Prof. Dr. rer. nat. 《e & i Elektrotechnik und Informationstechnik》2003,120(3):75-78
An overview of properties and recent achievements for AlGaN/GaN high electron mobility transistors (HEMT) on semi-insulating SiC substrate is given towards high power and broadband applications up to a frequency of 40 GHz. Starting from epitaxial growth and process technology we present state-of-the-art power results obtained at the Fraunhofer Institute (IAF) from AlGaN/GaN HEMTs on SiC. Further, a one-stage 16 GHz MMIC power amplifier circuit with 1.6 W output power is presented. This result represents the first AlGaN/GaN MMIC on SiC fabricated in Europe. 相似文献
16.
Due to the great potential of GaN based devices,the analysis of the growth of crack-free GaN with high quality has always been a research hotspot.In this paper,two methods for improving the property of the GaN epitaxial layer on Si (111) substrate are researched.Sample A,as a reference,only has an AlN buffer between the Si substrate and the epitaxy.In the following two samples,a GaN transition layer (sample B) and an AlGaN buffer (sample C) are grown on the AlN buffer separately.Both methods improve the quality of GaN.Meanwhile,using the second method,the residual tensile thermal stress decreases.To further study the impact of the two introduced layers,we investigate the stress condition of GaN epitaxial layer by Raman spectrum.According to the Raman spectrum,the calculated residual stress in the GaN epitaxial layer is approximately 0.72 GPa for sample B and 0.42 GPa for sample C.The photoluminescence property of GaN epitaxy is also investigated by room temperature PL spectrum. 相似文献
17.
M. A. L. Johnson Zhonghai Yu J. D. Brown N. A. El-Masry J. W. Cook Jr. J. F. Schetzina 《Journal of Electronic Materials》1999,28(3):295-300
Traditional epitaxial growth of GaN by metalorganic vapor phase epitaxy (MOVPE) on mismatched substrates such as sapphire
or SiC produces a columnar material consisting of many hexagonal grains ∼0.2–1.0 μm in diameter. The epitaxial-lateral-overgrowth
(ELO) process for GaN creates a new material: single-crystal GaN. We have studied the ELO process for GaN grown by MOVPE in
a vertical flow rotating substrate reactor. Characterization consisted of plan-view SEM and vertical-cross-section TEM studies,
which revealed a large reduction in dislocation density in the overgrown regions of the GaN. Panchromatic and monochromatic
cathodoluminescence images and spectra were used to study the spatial variation of the optical properties within the GaN ELO
samples. The effects of growth temperature and stripe material on the overgrown layers were examined. Through the use of a
higher substrate temperature during growth and the use of a SiNx stripe material, the overgrown crystal shape has a smooth 2D top surface with vertical sidewalls. Applying a second ELO step,
rotated by 60°, over a fully coalesced ELO layer yields a further reduction of defects in GaN overgrown surfaces. 相似文献
18.
A. F. Tsatsulnikov W. V. Lundin A. V. Sakharov E. E. Zavarin S. O. Usov A. E. Nikolaev M. A. Yagovkina V. M. Ustinov N. A. Cherkashin 《Semiconductors》2016,50(9):1241-1247
The epitaxial growth of InAlN layers and GaN/AlN/InAlN heterostructures for HEMTs in growth systems with horizontal reactors of the sizes 1 × 2", 3 × 2", and 6 × 2" is investigated. Studies of the structural properties of the grown InAlN layers and electrophysical parameters of the GaN/AlN/InAlN heterostructures show that the optimal quality of epitaxial growth is attained upon a compromise between the growth conditions for InGaN and AlGaN. A comparison of the epitaxial growth in different reactors shows that optimal conditions are realized in small-scale reactors which make possible the suppression of parasitic reactions in the gas phase. In addition, the size of the reactor should be sufficient to provide highly homogeneous heterostructure parameters over area for the subsequent fabrication of devices. The optimal compositions and thicknesses of the InAlN layer for attaining the highest conductance in GaN/AlN/InAlN transistor heterostructures. 相似文献