共查询到20条相似文献,搜索用时 15 毫秒
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Epitaxial lateral overgrowth (ELO) is a new technique to grow low-defect-density thin films on lattice-mismatched substrates.
For the ELO growth of CdTe and HgCdTe on Si substrate to be successful, the first requirement is that the growth should be
selective. To that end, we have used several mask materials, and several growth conditions in order to obtain selective growth.
A number of growth-experiments have been carried out, with temperatures in the range from 380°C to 550°C, and pressures in
the range from 380 torr to less than 20 torr. Perfectly selective growth of CdTe has been achieved on Si and GaAs substrates
using Si3N4 as the mask layer. Successful lateral epitaxial growth of CdTe was also achieved. 相似文献
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N.M. Jeutter M. Hennemeyer R. Stark A. Stierle W. Moritz 《Materials Science in Semiconductor Processing》2006,9(6):1079
The growth of Pr2O3 layers on Si(1 1 1) has been studied by X-ray diffraction, Low-energy electron diffraction (LEED) and atomic force microscopy (AFM). Pr2O3 starts to grow as a 0.6-nm thick layer corresponding to one unit cell of the hexagonal phase (1 ML). The X-ray results indicate that layers thicker than 0.6 nm do not grow with the hexagonal phase. Growth takes place at a sample temperature of 500–550 °C. Annealing of the monolayer in UHV at a temperature above 700 °C leads to the formation of Pr2O3 and PrSi2 islands. Silicide islands are found only at annealing in UHV and do not occur at annealing in oxygen atmosphere of 10−8 mbar. The LEED pattern after heating to 730 °C shows a (2×2) and (√3×√3) superstructure and after heating to 1000 °C a (1×5) superstructure occurs. The superstructures seen in the LEED pattern arise from silicide structures in the area between the islands. The silicide remains on the surface and cannot be removed with flashing to 1100 °C. Further deposition of Pr2O3 on the surface covered with silicide phases does not lead to growth of ordered layers. 相似文献
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Junichi Motohisa Chiharu Tazaki Tomoki Irisawa Masashi Akabori Takashi Fukui 《Journal of Electronic Materials》2000,29(1):140-145
We investigated the delta-doping (δ-doping) of Si using SiH4 on MOVPE-grown GaAs (001) vicinal surfaces to explore the possibility of selective incorporation of Si along atomic steps,
and to demonstrate doping quantum wires by the combination of multiatomic steps and wire-like doping. It was found that the
doping density on vicinal surfaces was enhanced as the misorientation angle was increased, which suggested the enhanced decomposition
of SiH4 and the selective incorporation of Si at step edges. It was also found that this selective incorporation could be enhanced
by annealing the surface prior to the δ-doping, which resulted from the reduced incorporation of Si at the terrace regions.
Anisotropic electron transport properties which are expected from the wire-like incorporation along step edges are also discussed. 相似文献
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K. Yuan K. Radhakrishnan H. Q. Zheng S. F. Yoon 《Materials Science in Semiconductor Processing》2001,4(6):2331
Compositionally graded InxGa1−xP (x=0.48→x=1) metamorphic layers have been grown on GaAs substrate by solid source molecular beam epitaxy using a valved phosphorus cracker cell. Three series of samples were grown to optimize the growth temperature, V/III ratio and grading rate of the buffer layer. X-ray diffraction (XRD) and photoluminescence (PL) were used to characterize the samples. The following results have been obtained: (1) XRD measurement shows that all the samples are nearly fully strain relaxed and the strain relaxation ratio is about 96%; (2) the full-width at half-maximum (FWHM) of the XRD peak shows that the sample grown at 480°C offers better material quality; (3) the grading rate does not influence the FWHM of XRD and PL results; (4) adjustment of the V/III ratio from 10 to 20 improves the FWHM of XRD peak, and the linewidth of PL peak is close to the data obtained for the lattice-matched sample on InP substrate. The optimization of growth conditions will benefit the metamorphic HEMTs grown on GaAs using graded InGaP as buffer layers. 相似文献
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研究了分子束外延GaAs/Si光致发光谱的激发强度和温度依赖关系。确定出2个本征发光峰,分别对应于导带至m_J=±3/2和m_J=±1/2价带的复合。这种价带的移动和分裂归因于由GaAs和Si的热膨胀系数不同所引起的GaAs层双轴张应力。还观测到4个非本征发光峰,分别为导带至m_J=±1/2碳受主态发光、可能与缺陷有关的发光以及可能由Mn和Cu受主杂质引起的发光。室温下将GaAs/Si和GaAs/GaAs材料的光反射谱进行比较,前者明显向低能移动约8meV,观测到3个特征谱结构,与光致发光结果相一致。 相似文献
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GaN films have been grown at 1050 °C on porous silicon (PS) substrates by metalorganic vapour phase epitaxy. The annealing phase of PS has been studied in temperature range from 300 to 1000 °C during 10 min under a mixture of ammonia (NH3) and hydrogen (H2). The PS samples were characterized after annealing by scanning electronic microscope (SEM). We observed that the annealing under the GaN growth conditions does not affect the porous structure.For the growth of the active GaN layer we used a thin AlN layer in order to improve wetting between GaN and PS/Si substrate. The growth of AlN and GaN films was controlled by laser-reflectometry. We estimated the porosity of PS samples from the evolution of the reflectivity signal during the AlN growth. The crystalline quality and surface morphology of GaN films were determined by X-ray diffraction and SEM, respectively. Preferential growth of hexagonal GaN with (0002) direction is observed and is clearly improved when the thickness of AlN layer increases. Epitaxial GaN layers were characterized by photoluminescence. 相似文献
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The growth of Ge islands on Si(110) substrates by low pressure chemical vapour deposition has been studied. Atomic force microscopy images reveal that multifaceted dome shaped islands appear on samples where the two-dimensional (2D) to three-dimensional (3D) growth mode changeover has occurred. Photoluminescence (PL) spectroscopy was used to investigate the growth as a function of the Ge coverage. The excitation power dependence of island PL spectra allowed one to point out a band filling effect and to determine the efficiency of radiative recombinations. In addition, island PL peak evolution with temperature underlined a good hole confinement. 相似文献
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Structures with vertically correlated self-organised InAs quantum dots (QDs) in a GaAs matrix were grown by the low-pressure metal-organic vapour phase epitaxy (MOVPE) and characterised by different microscopic techniques. Photoluminescence in combination with photomodulated reflectance spectroscopy were applied for characterisation of QDs structures. We show that combination of both methods allows detecting optical transitions originating both from QDs and wetting (separation) layers, which can be than compared with those obtained from numerical simulations. On the basis of obtained results, we demonstrate that photoreflectance spectroscopy is an excellent tool for characterisation of QDs structures wetting layers and for identification of spacer thicknesses in vertically stacked QDs structures. 相似文献
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Zhigang Jia Qi Wang Xiaomin Ren Xiaolong Liu Yifan Wang Yingce Yan Shiwei Cai Xia Zhang Yongqing Huang 《Materials Science in Semiconductor Processing》2013,16(6):1713-1717
Boron-containing GaAsSb/GaAs quantum wells (QWs) with different antimony (Sb) mole fractions were grown by low-pressure metal–organic chemical vapor deposition for the first time. The effects of boron incorporation on the performance of GaAsSb/GaAs QWs are discussed. For samples with low compressive strain, injection of triethylboron can enhance the Sb content and increase the compressive strain, although boron incorporation can lead to a reduction in strain. This effect was less for strained GaAsSb/GaAs QWs, so the compressive strain of these QWs did not vary. Room-temperature photoluminescence emission at 1116 nm with a full-width at half-maximum (FWHM) value of 56 meV was obtained for strained BGaAsSb/GaAs QWs. 相似文献
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J. Misiewicz K. Jezierski P. Sitarek P. Markiewicz R. Korbutowicz M. Panek B.
ciana M. Taczaa 《Advanced functional materials》1995,5(6):321-327
Epitaxial undoped and doped (Si and Zn) GaAs and GaAIAs layers as well as heterostructures of GaAs/GaAIAs have been grown in an atmospheric pressure, vertical MOCVD system. Room temperature photoreflectance (PR) has been applied to characterise the layers and heterostructures as well as multiple quantum wells. The surface- and interface-related PR has been studied by application of Kramers–Kronig analysis. A decomposition of the PR spectrum into spectra connected with the surface region and with the interface has been proposed. 相似文献
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生长了短周期 Al Ga As/ Ga As超晶格 ,并通过双晶 X射线衍射谱 ,对 MOCVD超薄层Al Ga As、Ga As的生长进行了研究。从衍射谱卫星峰的级数及 Pendellosong干涉条纹的出现 ,定性地对晶格结构及界面作出评价。 X光衍射测量结果与 HEMT结构电学性能测试结果有较好的对应关系。 相似文献
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Shen Xiaoming Wang Yutian Wang Jianfeng Liu Jianping Zhang Jicai Guo Liping Jia Quanjie Jiang Xiaoming Hu Zhengfei Y 《半导体学报》2005,26(4):645-650
GaN buffer layers (thickness ~60nm) grown on GaAs(001) by low-temperature MOCVD are investigated by X-ray diffraction pole figure measurements using synchrotron radiation in order to understand the heteroepitaxial growth features of GaN on GaAs(001) substrates.In addition to the epitaxially aligned crystallites,their corresponding twins of the first and the second order are found in the Xray diffraction pole figures.Moreover,{111} φ scans with χ at 55°reveal the abnormal distribution of Bragg diffractions.The extra intensity maxima in the pole figures shows that the process of twinning plays a dominating role during the growth process.It is suggested that the polarity of {111} facets emerged on (001) surface will affect the growth twin nucleation at the initial stages of GaN growth on GaAs(001) substrates.It is proposed that twinning is prone to occurring on {111}B,Nterminated facets. 相似文献
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M.A. Abid H. Abu Hassan Z. Hassan S.S. Ng S.K. Mohd Bakhori N.H.Abd. Raof 《Materials Science in Semiconductor Processing》2011,14(2):164-169
High-resolution X-ray diffraction (HR-XRD) with rocking curve, atomic force microscopy (AFM) and photoluminescence (PL) spectroscopy have been performed on high-quality quaternary AlxInyGa1−x−yN thin films at room temperature. The AlxInyGa1−x−yN films were grown on c-plane (0 0 0 1) sapphire substrates with AlN as buffer layers using a molecular beam epitaxy (MBE) technique with aluminum (Al) mole fractions x ranging from 0.0 to 0.2 and constant indium (In) mole fraction y=0.1. HR-XRD measurements confirmed the high crystalline quality of these alloys without any phase separation. The X-ray rocking curve of AlxInyGa1−x−yN films typically shows full widths at half maximum (FWHM) intensity between 14.4 and 28.8 arcmin. AFM measurements revealed a two-dimensional (2D) growth mode with a smooth surface morphology of quaternary epilayers. PL spectra exhibited both an enhancement of the integrated intensity and an increasing blueshift with increased Al content with reference to the ternary sample In0.1Ga0.90N. Both effects arise from Al-enhanced exciton localization. PL was used to determine the behavior of the energy band gap of the quaternary films, which was found to increase with increasing Al composition from 0.05 to 0.2. This trend is expected since the incorporation of Al increases the energy band gap of ternary In0.1Ga0.90N (3.004 eV). We have also investigated the bowing parameter for the variation of energy band gaps and found it to be very sensitive on the Al composition. A value of b=10.4 has been obtained for our quaternary AlxInyGa1−x−yN alloys. 相似文献
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Kent D. Choquette M. Hong J. P. Mannaerts D. J. Siconolfi R. P. Frankenthal F. A. Baiocchi R. C. Wetzel R. S. Freund 《Journal of Electronic Materials》1992,21(1):17-21
In situ deposition of single crystal epitaxial and textured polycrystalline gold films on plasma-cleaned or plasma-etched GaAs substrates
is accomplished in an ultrahigh vacuum integrated processing facility. Au/GaAs samples are characterized using reflection
high energy electron diffraction, Auger electron spectroscopy, and ion channeling. Au crystallinity in films deposited at
100° C is shown to strongly depend on the GaAs surface cleanliness after plasma processing. Heating the substrate to 250°
C after plasma processing subsequently yields epitaxial Au films; omitting the heating procedure results in polycrystalline
Au films. The substrate thermal treatment removes residual physisorbed gas molecules and reaction products from the GaAs surface.
Epitaxial Au films contain significantly less Ga and As on the free surface of Au than polycrystalline films, and no interaction
between epitaxial Au and GaAs is observed. 相似文献