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1.
近年来,图形化蓝宝石衬底(PSS)作为GaN基LED外延衬底材料被广泛应用。采用感应耦合等离子体(ICP)技术对涂覆有光刻胶阵列图案的蓝宝石衬底进行刻蚀。通过研究及优化不同ICP刻蚀工艺参数对刻蚀速率和选择比的影响,分别成功制备出蒙古包形和圆锥形图形化蓝宝石衬底片,并在其表面完成InGaN/GaN多量子阱外延及芯片工艺。借助光致发光和电致发光等手段测试其LED器件的光电学性能。实验结果发现圆锥形的图形化蓝宝石衬底拥有更强的光功率和更窄的半峰宽,说明这种形貌的衬底在GaN外延时有效减少了晶格失配造成的缺陷,提高了晶体质量,从而更有效地增加LED出光效率。  相似文献   

2.
为了提升垂直结构LED提取效率,针对器件侧壁出光的研究越发引起研究人员的关注。由于GaN的高折射率,大部分有源区发出的光线将被限制在GaN层内横向传输。对不同刻蚀倾角侧面的光提取效率进行分析模拟,模拟结果显示,LED的提取效率可以通过侧壁倾斜角度的优化得以提升。实验结果表明,特定侧壁倾角器件的提取效率相比较垂直侧壁提高了18.75%,电致发光光谱测试(EL)结果表明,实验结论与理论计算值基本吻合。本结论对垂直结构GaN基LED器件的优化设计与性能提升有重要指导意义。  相似文献   

3.
表面粗化对GaN基垂直结构LED出光效率的影响   总被引:2,自引:1,他引:1  
用加热后的KOH水溶液腐蚀GaN材料的N极性面,用以提高GaN基垂直结构发光二极管(LED)的出光效率。经过湿法腐蚀后,构成N极性面的表面晶粒尺寸和密度成为影响垂直结构LED提取效率的主要因素,通过分析不同腐蚀条件下晶粒尺寸和密度与出光效率间的关系,得到最优化的粗化条件,使得器件的提取效率达到最佳。经由浓度为30%、温度为60℃的KOH溶液腐蚀后,未封装的垂直结构LED芯片的提取效率增加了近1倍。  相似文献   

4.
图形化蓝宝石衬底GaN基LED的研究进展   总被引:3,自引:0,他引:3  
蓝宝石衬底作为发光二极管最常用的衬底,经过不断发展,在克服其与GaN间晶格失配和热膨胀失配问题上,研究人员不断提出解决方案。近期发展起来的图形化衬底技术,除了能减少生长在蓝宝石衬底上GaN之间的差排缺陷,提高磊晶质量以解决失配问题,更能提高LED的出光效率。从衬底图形的形状、尺寸、制备工艺出发,回顾了图形化蓝宝石衬底GaN基LED的研究进展,详细介绍了近年来关于图形化衬底技术与其他技术在提高LED性能方面的结合,总结了图形化蓝宝石衬底应用于大尺寸芯片的优势,并对其未来在大功率照明市场的应用进行了展望。  相似文献   

5.
为了制作高亮度LED,需要在图形化蓝宝石衬底上生长GaN材料。通过光刻在平坦蓝宝石衬底上制作掩膜图形,通过刻蚀将图形转移到蓝宝石衬底,得到图形化蓝宝石衬底。在图形化蓝宝石衬底上进行GaN的侧向外延生长,并做后续处理,就制成了基于图形化蓝宝石衬底的高亮度LED。图形化蓝宝石衬底上GaN的侧向外延生长使得外延材料的位错密度从1010 cm-2降低到107 cm-2,这减少了发生非辐射复合的载流子,多量子阱发射更多的光子,LED的内量子效率提高。此外,图形化蓝宝石衬底能够有效散射从多量子阱射出的光线,使得出射光射到逃离区的几率更大,从而提高光萃取率。内量子效率和光萃取率的提高大大改善了LED的光电特性。  相似文献   

6.
设计了方形和阶梯状两大类的图形化蓝宝石衬底(PSS), 使用Crosslight公司的工艺软件CSuprem建立了三维的方形和阶梯状两类图形衬底GaN LED器件, 然后使用APSYS软件模拟计算出它们的光电特性。并且对方形图形衬底的刻蚀深度进行了优化, 通过对模拟结果的比较得到刻蚀深度与边长的比值为0.4时, 这种方形图形衬底GaN LED的光提取效率最高, 且比平面衬底提高了20.13%。对阶梯状图形衬底的阶梯层数进行了比较, 发现随着阶梯层数的增加, 光提取效率也随着增加, 阶梯状层数为5时, 光提取效率比平面衬底提高了30.03%。并对方形PSS LED进行了实验验证。  相似文献   

7.
因蓝宝石具有良好的稳定性能,且其生产技术成熟,是目前异质外延GaN应用最广泛的衬底材料之一.采用图形化蓝宝石衬底技术可以降低GaN外延层材料的位错密度,提高LED的内量子效率,同时提高LED出光效率提高,近年来引起了国内外的广泛关注.概述了图形化蓝宝石衬底的研究进展,包括图形化蓝宝石衬底的制备工艺、图形尺寸、图形形状及图形化蓝宝石衬底的作用机理;详细介绍了凹槽状、圆孔状、圆锥形、梯形和半球状5种图形形状,并分析了GaN材料在不同图形形状的图形化蓝宝石衬底上的生长机理及不同图形形状对GaN基LED器件性能的影响.对图形化蓝宝石衬底技术的研究方向进行了展望,提出了亟待研究和解决的问题.  相似文献   

8.
通过模拟计算,分析了阵列微透镜粗化对倒装结构GaN基LED提取效率的影响.并采用感应耦合等离子(ICP)干法刻蚀技术在蓝宝石表面制备阵列微透镜,实现倒装结构GaN基LED出光面粗化.测试结果表明,相对于普通倒装结构,阵列微透镜表面粗化可以使LED提取效率提高约50%,测试结果与模拟计算值相符合.  相似文献   

9.
通过模拟计算,分析了阵列微透镜粗化对倒装结构GaN基LED提取效率的影响.并采用感应耦合等离子(ICP)干法刻蚀技术在蓝宝石表面制备阵列微透镜,实现倒装结构GaN基LED出光面粗化.测试结果表明,相对于普通倒装结构,阵列微透镜表面粗化可以使LED提取效率提高约50%,测试结果与模拟计算值相符合.  相似文献   

10.
设计了InGaN/GaN超晶格垒层替代p-GaN和n-GaN附近传统GaN垒层的InGaN/GaN多量子阱(MQW)发光二极管(LEDs)结构。通过数值方法模拟出两种LED结构的光功率-电压(L-V)曲线、电致发光(EL)谱、能带图、电子浓度分布和辐射复合速率。结果表明InGaN/GaN超晶格替代n-GaN附近GaN垒层的LED结构比替代p-GaN附近GaN垒层的LED显示出更高的发光强度。这种发光增强的原因是InGaN/GaN超晶格替代n-GaN附近GaN垒层可以提高电子注入效率和辐射复合速率。  相似文献   

11.
DUV lithography, using the 248 nm wavelength, is a viable manufacturing option for devices with features at 130 nm and less. Given the low kl value of the lithography, integrated process development is a necessary method for achieving acceptable process latitude. The application of assist features for rule based OPC requires the simultaneous optimization of the mask, illumination optics and the resist.Described in this paper are the details involved in optimizing each of these aspects for line and space imaging.A reference pitch is first chosen to determine how the optics will be set. The ideal sigma setting is determined by a simple geometrically derived expression. The inner and outer machine settings are determined, in turn,with the simulation of a figure of merit. The maximum value of the response surface of this FOM occurs at the optimal sigma settings. Experimental confirmation of this is shown in the paper.Assist features are used to modify the aerial image of the more isolated images on the mask. The effect that the diffraction of the scattering bars (SBs) has on the image intensity distribution is explained. Rules for determining the size and placement of SBs are also given.Resist is optimized for use with off-axis illumination and assist features. A general explanation of the material' s effect is discussed along with the affect on the through-pitch bias. The paper culminates with the showing of the lithographic results from the fully optimized system.  相似文献   

12.
This paper presents a new method to increase the waveguide coupling efficiency in hybrid silicon lasers. We find that the propagation constant of the InGaAsP emitting layer can be equal to that of the Si resonant layer through improving the design size of the InP waveguide. The coupling power achieves 42% of the total power in the hybrid lasers when the thickness of the bonding layer is 100 nm. Our result is very close to 50% of the total power reported by Intel when the thickness of the thin bonding layer is less than 5 nm. Therefore, our invariable coupling power technique is simpler than Intel's.  相似文献   

13.
The relation between the power of the Brillouin signal and the strain is one of the bases of the distributed fiber sensors of temperature and strain. The coefficient of the Bfillouin gain can be changed by the temperature and the strain that will affect the power of the Brillouin scattering. The relation between the change of the Brillouin gain coefficient and the strain is thought to be linear by many researchers. However, it is not always linear based on the theoretical analysis and numerical simulation. Therefore, errors will be caused if the relation between the change of the Brillouin gain coefficient and the strain is regarded as to be linear approximately for measuring the temperature and the strain. For this reason, the influence of the parameters on the Brillouin gain coefficient is proposed through theoretical analysis and numerical simulation.  相似文献   

14.
Today, micro-system technology and the development of new MEMS (Micro-Electro-Mechanical Systems) are emerging rapidly. In order for this development to become a success in the long run, measurement systems have to ensure product quality. Most often, MEMS have to be tested by means of functionality or destructive tests. One reason for this is that there are no suitable systems or sensing probes available which can be used for the measurement of quasi inaccessible features like small holes or cavities. We present a measurement system that could be used for these kinds of measurements. The system combines a fiber optical, miniaturized sensing probe with low-coherence interferometry, so that absolute distance measurements with nanometer accuracy are possible.  相似文献   

15.
The parallel thinning algorithm with two subiterations is improved in this paper. By analyzing the notions of connected components and passes, a conclusion is drawn that the number of passes and the number of eight-connected components are equal. Then the expression of the number of eight-connected components is obtained which replaces the old one in the algorithm. And a reserving condition is proposed by experiments, which alleviates the excess deletion where a diagonal line and a beeline intersect. The experimental results demonstrate that the thinned curve is almost located in the middle of the original curve connectivelv with single pixel width and the processing speed is high.  相似文献   

16.
From its emergence in the late 1980s as a lower cost alternative to early EEPROM technologies, flash memory has evolved to higher densities and speedsand rapidly growing acceptance in mobile applications.In the process, flash memory devices have placed increased test requirements on manufacturers. Today, as flash device test grows in importance in China, manufacturers face growing pressure for reduced cost-oftest, increased throughput and greater return on investment for test equipment. At the same time, the move to integrated flash packages for contactless smart card applications adds a significant further challenge to manufacturers seeking rapid, low-cost test.  相似文献   

17.
Waveguide multilayer optical card (WMOC) is a novel storage device of three-dimensional optical information. An advanced readout system fitting for the WMOC is introduced in this paper. The hardware mainly consists of the light source for reading, WMOC, motorized stages addressing unit, microscope imaging unit, CCD detecting unit and PC controlling & processing unit. The movement of the precision motorized stage is controlled by the computer through Visual Basic (VB) language in software. A control panel is also designed to get the layer address and the page address through which the position of the motorized stages can be changed. The WMOC readout system is easy to manage and the readout result is directly displayed on computer monitor.  相似文献   

18.
It is well known that adding more antennas at the transmitter or at the receiver may offer larger channel capacity in the multiple-input multiple-output(MIMO) communication systems. In this letter, a simple proof is presented for the fact that the channel capacity increases with an increase in the number of receiving antennas. The proof is based on the famous capacity formula of Foschini and Gans with matrix theory.  相似文献   

19.
The effect of laser microbeam trapping the bioparticles has been appfied widely in the biology .However the micromechanism of the acting that realizes the laser-microbeam trapping bioparticles is still lacking. In this paper ,the act microchenism of the gradiant force of laser microbeam for the bioparticles is analysed by means of quantum theory ,The result accords with our experiment.  相似文献   

20.
We have fabricated the white organic light-emitting devices (WOLEDs) based on 4,4' -bis(2,2 -diphenyl vinyl)-1,1' - biphenyl (DPVBi) and phosphorescence sensitized 5,6,11,12,-tetraphenylnaphthacene (rubrene). The device structure is ITO/2T-NATA (20 nm)/NPBX (20 nm)/CBP: x%Ir(ppy)3:0.5% rubrene (8 nm)/NPBX (5 nm)/DPVBi (30 nm)/Alq(30 nm)/LiF(0.5 nm)/A1. In the devices, DPVBi acts as a blue light-emitting layer, the rubrene is sensitized by a phosphorescent material, fac tris (2-phenylpyridine) iridium [Ir(ppy)3], acts as a yellow light-emitting layer, and N,N' -bis- (1-naphthyl)- N,N' -diphenyl -1, 1' -biphenyl-4,4' -diamine (NPBX) acts as a hole transporting and exciton blocker layer, respectively. When the concentration of Ir (PPY)3 is 6wt%, the maximum luminance is 24960 cd/m^2 at an applied voltage of 15 V, and the maximum luminous efficiency is 5.17 cd/A at an applied voltage of 8 V.  相似文献   

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