共查询到20条相似文献,搜索用时 31 毫秒
1.
Q. Xu J. W. P. Hsu E. A. Fitzgerald J. M. Kuo Y. H. Xie P. J. Silverman 《Journal of Electronic Materials》1996,25(6):1009-1013
The surface morphology of GaAs films grown on Ge substrates is studied by scanning force microscopy. We find a dramatic difference
arising from Ga as opposed to As prelayers in the formation of anti-phase boundaries (APBs), surface features near threading
dislocations, and surface roughness, for films as thick as 1 μm. Ga prelayer samples are smooth; thin films display some APBs
with predominantly one growth domain while the 1 μm thick film displays the morphology of a homoepitaxial GaAs film. In contrast,
As prelayer samples are rough with complicated APB structures, which can be attributed to the increase in single steps during
As2 deposition. 相似文献
2.
W. T. Tsang 《Journal of Electronic Materials》1986,15(4):235-245
The growth kinetics of chemical beam epitaxy (CBE) were investigated with the growth of GaAs, AIGaAs, InP, and InGaAs. Results
obtained with epilayers grown by using trimethylarsine (TMAs) and triethylphosphine (TEP) instead of arsine (AsH3) and phosphine
(PH3) were reviewed with some additional results. The CBE grown epilayers have similar optical quality to those grown by molecular
beam epitaxy (MBE). Superlattices of GaAs/AlGaAs with abrupt interfaces have been prepared. Since trimethylindium (TMIn) and
triethylgallium (TEGa) used in the growth of InGaAs emerged as a single mixed beam, spatial composition uniformity was automatically
achieved without the need of substrate rotation in the InGaAs epilayers grown. Lattice-mismatch Δα/α< 1 x 10-3 have been reproducibly obtained. For epilayers grown with high purity TMAs source, room-temperature electron mobility as
high as 9000 cm2/V sec and concentrations of ˜7 x 1015 cm-3 were produced. In general, the electron mobilities were as good as those obtained from low-pressure metalorganic chemical
vapor deposition. (MO-CVD). Unlike MBE, since the In and Ga were derived by the pyrolysis of TMIn and TEGa molecules at the
heated substrate surface, respectively, oval defects observed in MBE grown epilayers due to Ga splitting from Ga melt were
not present in CBE grown epilayers. This is important for integrated circuit applications. Unlike MO-CVD, the beam nature
of CBE allows for selective area growth of epilayers with well-defined smooth edges using mask shadowing techniques. Typically,
growth rates of 2-5μm/h for InP, 2-6μm/h for GaAs and AIGaAs, and 2-5μm/h for InGaAs were used. 相似文献
3.
采用组分跳变和低温大失配缓冲层技术在GaAs衬底上外延了In0.3Ga0.7As材料。测试结果表明,采用组分跳变缓冲层生长的In0.3Ga0.7As主要依靠逐层间产生失配位错来释放应力,并导致表面形成纵横交错的Cross-hatch形貌;而采用低温大失配缓冲层技术则主要通过在低温缓冲层中形成大量缺陷来充分释放应力,并在后续外延的In0.3Ga0.7As表面没有与失配位错相关的Cross-hatch形貌出现。此外,仅需50nm厚的低温大失配缓冲层即可促使In0.3Ga0.7As中的应力完全释放,这种超薄缓冲层技术在工业批产中显得更为经济。 相似文献
4.
使用三氯硅烷(TCS)作为含氯生长源,在多片外延设备生长了高质量的4H-SiC外延材料.研究了原位预刻蚀气体HCl流量和刻蚀时间对SiC外延材料表面三角形缺陷的影响,使用光学显微镜和表面缺陷分析仪对SiC外延材料表面缺陷进行表征测试和统计,使用傅里叶红外测试仪(FTIR)和原子力显微镜(AFM)对外延材料表面形貌进行表征.结果表明,预刻蚀气体体积流量和时间对4英寸SiC外延材料表面三角形缺陷影响明显,随着HCl体积流量和时间的增加,材料表面的三角形缺陷密度先减小后增加,在HCl流量为100 mL/min、刻蚀时间为20 min时,三角形缺陷密度最低达到0.47cm-2.此外,通过调整C/Si比和载气体积流量等参数,使4英寸SiC外延材料掺杂浓度不均匀性和厚度不均匀性均得到有效改善,结果表明该外延片质量满足SiC电力电子器件的应用. 相似文献
5.
Kai Qiu X.H. Li F. Zhong Z.J. Yin X.D. Luo C.J. Ji Q.F. Han J.R. Chen X.C. Cao X.J. Xie Y.Q. Wang 《Journal of Electronic Materials》2007,36(4):436-441
This paper reports the properties of GaN grown by the hydride vapor-phase epitaxy (HVPE) technique on buffer layers with different
polarities. The N-, mixed-, and Ga-polarity buffer layers were grown by molecular-beam epitaxy (MBE) on sapphire (0001) substrates;
then, thicker GaN epilayers were grown on these by HVPE. The surface morphology, structural, and optical properties of these
HVPE-GaN epilayers were characterized by atomic force microscopy (AFM), x-ray diffraction (XRD), scanning electron microscopy,
and photoluminescence (PL) spectroscopy. The results indicate that the crystallinity of these HVPE-GaN epilayers depends on
the polarity of the buffer layer. 相似文献
6.
报导了在n型(100)GaSb衬底上,温度为520—530℃时,用液相外延的方法实现了组分在0≤x≤0.19,0≤y≤0.14范围内的Ga_(1-x)In_xAs_ySb_(1-y)四元合金半导体的生长。X射线双晶衍射,电子探针及光学显微镜的观察和分析测试表明:所得外延层的表面形貌和界面特性优良,组分分布和层厚均匀,晶格匹配及单晶性能良好。对外延层表面的氧化情况使用Auger能谱仪进行测试分析。另外,对生长中存在的一些问题进行了讨论。 相似文献
7.
Z. C. Feng A. Rohatgi C. C. Tin R. Hu A. T. S. Wee K. P. Se 《Journal of Electronic Materials》1996,25(5):917-923
A series of epitaxial 4H-SiC thin films grown by low pressure chemical vapor deposition (LPCVD) were characterized using various
techniques, including x-ray diffraction (XRD), Fourier transform infrared (FTIR) reflectance, Raman scattering, and x-ray
photoelectron spectroscopy (XPS). The epilayers were grown on heavily doped n-type 4H-SiC substrates using different gas compositions.
XRD showed that the thin films were single crystal. Raman scattering identified the films to be 4H polytype. FTIR reflectivity
spectra indicated improvement in the film quality over that of the substrate and atmospheric pressure-grown epilayers. XPS
scans revealed the existence of Si, C, and O along with C-contaminant species in the form of CH and carbon oxides. Variations
in crystalline quality, optical, and surface properties with the growth conditions were studied. This study also provides
an important comparison between low and atmospheric pressure-grown 4H-SiC epilayers. 相似文献
8.
InAlN epilayers were grown on high quality GaN and A1N templates with the same growth parameters. Measurement results showed that two samples had the same In content of~16%,while the crystal quality and surface topography of the InAlN epilayer grown on the AlN template,with 282.3"(002) full width at half maximum (FWHM) of rocking curve,313.5"(102) FWHM,surface roughness of 0.39 nm and V-pit density of 2.8×108 cm-2,were better than that of the InAlN epilayer grown on the GaN template,309.3",339.1",0.593 nm and 4.2×108 cm-2.A primary conclusion was proposed that both the crystal quality and the surface topography of the InAlN epilayer grown on the AlN template were better than that of the InAlN epilayer grown on the GaN template. Therefore,the AlN template was a better choice than the GaN template for getting high quality InAlN epilayers. 相似文献
9.
AlxGa1−xAs epilayers were grown directly on different AlxGa1−xAs substrate-layers by metalorganic chemical vapor deposition (MOCVD). The quality of AlxGa1−-xAs layers was significantly improved when Se-doped AlxGa1−xAs substrate-layers were used. Al0.13Ga0.87As epilayers with excellent morphology, optical, and crystal quality were grown on Se-doped Al0.26Ga0.74As. The full width at half maximum of the bound exciton peak as low as 4.51 meV was measured by low-temperature (14.9K) photoluminescence.
The improvement is attributed to a Se passivation effect at the surface of Se-doped AlxGa1−xAs substrate-layers. Results suggest that Se will reduce and delay the formation of native oxides. 相似文献
10.
Si-doped GaN epitaxial layers have been grown at 1050 °C on optimized-AlN buffered (0001) sapphire substrates by atmospheric pressure metalorganic vapor phase epitaxy. In order to investigate the Si effect on the surface morphology of GaN epilayers, several samples were grown by varying the silane partial pressure. When the silane partial pressure increases above 1.7×10−8 atm, the surface quality becomes rough. This shows the Si surfactant effect. A correlation between an in situ laser reflectometry and ex situ optical and atomic force microscopy characterizations on the one hand and between electrical properties and surface quality on the other hand were made. As the electron concentration increases, the surface becomes more and more rough and the mobility drops dramatically. 相似文献
11.
采用液相外延技术生长了InAs基室温红外探测器件材料,通过光学显微镜、扫描电子显微镜、X射线衍射仪分析了外延材料表面形貌、截面形貌与晶格失配的关系。分析发现,不恰当的晶体晶格常数匹配度会导致材料表面形貌变差,降低材料的结晶质量,晶格失配在0.22%左右的InAs基外延材料表面形貌较好,缺陷少,晶体质量较好。在此基础上,成功制备出室温探测率D*为6.8×109 cm·Hz1/2·W-1的InAs基室温中波红外探测器,这一性能与国际上红外探测器领军企业美国Teledyne Judson Technologies和日本滨松株式会社的商用InAs基红外探测器性能处于同等水平。 相似文献
12.
用分子束外延方法制备了具有GaInAs组分渐变缓冲层和不具有GaInAs组分渐变缓冲层的Ga0.9In0.1As/GaAs结构的外延材料。利用高分辨率X射线衍射法(HRXRD)对制备的两种样品分别进行了测试分析。实验结果表明,GaInAs组分渐变缓冲层对外延生长在GaAs衬底上的Ga0.9In0.1As外延材料的晶体质量具有显著的改善作用,极大降低了由于外延层与衬底晶格不匹配所带来的影响。从X射线倒易空间衍射(RSM)二维图谱结果来看,具有GaInAs组分渐变缓冲层结构的样品,其Ga0.9In0.1As外延层与GaInAs组分渐变缓冲层接近完全弛豫,Ga0.9In0.1As外延层的应变降低,表面残留应力小于0.06%,同时,GaAs衬底与Ga0.9In0.1As外延层之间的偏移夹角明显变小。 相似文献
13.
采用As2和As4模式的新型全固源InAsP分子束外延生长 总被引:1,自引:1,他引:0
在国产分子束外延设备的基础上,利用新型阀控裂解As源炉,对As2和As4的生长特性进行了全面的研究.以As2和As4两种模式,在(001)InP衬底上生长了高质量的InAsP体材料和InAsyP1-y/InP多量子阱样品.材料质量用X射线衍射(XRD)以及室温和低温的光致发光(PL)测定.实验发现,两种模式生长的样品的晶体结构质量相当,但As2的吸附系数明显大于As4的吸附系数.另外,用As2模式生长的多量子阱样品的室温光学特性优于As4模式生长的样品,但在低温时,二者几乎相同,这是由As4较为复杂的生长机制所引入的缺陷造成的. 相似文献
14.
15.
用液相外延法生长3~7μm波段InAs/InAs1-ySby及其光学和电学性质 总被引:2,自引:2,他引:0
用液相外延(LPE)法在InAs衬底上生长了3~7μm波段的InAs1-ySby外延层,研究了外延多层的组份与禁带宽度和晶格常数的关系。用光学显微镜、傅立叶变换红外(FTIR)透射、光荧光(PL)谱测试以及偏振光椭圆仪研究了外延材料的光学特性。电学性质是将计算值与实测有效霍尔(Hall)参数的厚度关系拟合得到的。结果表明,本文生长的材料在中红外光伏型探测器上具有良好的应用前景。 相似文献
16.
对在SiC衬底上采用MOCVD方法制备的GaN和GaN:Mg薄膜进行X射线衍射(XRD)、扫描电镜(SEM)和拉曼散射光谱的对比研究发现:两种样品均处于张力作用之下,但是GaN:Mg样品却由于Mg的掺杂会在样品中引入更多的缺陷和位错加剧薄膜的无序化程度,致使薄膜质量变差;其次因为Mg原子半径比Ga原子半径大,所以当Mg替代Ga以后会引发压力应力,从而使薄膜张力减小,最后通过计算说明对于GaN:Mg样品而言,除了载流子以外,薄膜质量同样也会对A1(LO)模式产生影响. 相似文献
17.
对在SiC衬底上采用MOCVD方法制备的GaN和GaN :Mg薄膜进行X射线衍射 (XRD)、扫描电镜 (SEM)和拉曼散射光谱的对比研究发现 :两种样品均处于张力作用之下 ,但是GaN∶Mg样品却由于Mg的掺杂会在样品中引入更多的缺陷和位错加剧薄膜的无序化程度 ,致使薄膜质量变差 ;其次因为Mg原子半径比Ga原子半径大 ,所以当Mg替代Ga以后会引发压力应力 ,从而使薄膜张力减小 ,最后通过计算说明对于GaN :Mg样品而言 ,除了载流子以外 ,薄膜质量同样也会对A1(LO)模式产生影 相似文献
18.
载气流量对HVPE外延生长GaN膜光学性质的影响 总被引:2,自引:0,他引:2
研究了利用水平氢化物气相外延 (HVPE)系统在蓝宝石衬底上外延氮化镓 (Ga N)的生长规律 ,重点研究了作为载气的氮气流量对 Ga N膜的结构及光学性质的影响。观察到载气流量对预反应的强弱有很大影响 ,外延膜的质量和生长速度对载气流量极为敏感。当载气流量较小时 ,样品的 X射线衍射谱 (XRD)中出现了杂峰(1 0 -1 1 )和 (1 1 -2 0 ) ,相应的光致发光谱 (PL)中出现了黄带 (YL) ,靠近带边有杂质态。而当载气流量增大时 ,样品质量改善。Ga N外延膜的结构和光学性质的相关性表明深能级的黄带与生长过程中产生的非 c轴方向晶面有关 ,据此我们推测 :Ga空位与束缚在 (1 0 -1 1 )和 (1 1 -2 0 )等原子面上的杂质构成复合结构 ,这些复合结构所产生的深能级对黄带的发射有贡献 ;由于预反应使生长过程中混入的附加产物及杂质对带边发射有重要影响 相似文献
19.
H. Wang S.L. Li H. Xiong Z.H. Wu J.N. Dai Y. Tian Y.-Y. Fang C.Q. Chen 《Journal of Electronic Materials》2012,41(3):466-470
AlN epilayers were grown directly on sapphire (0001) substrates using a combined growth scheme, consisting of a low-temperature
nucleation layer and a second layer grown by high-temperature pulsed atomic layer epitaxy via metalorganic chemical vapor
deposition. With an emphasis on the nucleation layer, its growth temperature was varied from 470°C to 870°C, and obvious differences
in the surface morphology, crystal quality, and strain states of the overall AlN epilayers were observed. Based on atomic
force microscopy, x-ray diffraction, and Raman spectroscopy results, these differences are ascribed to the nucleation sites
and the subsequent grain size. Due to the enhanced mobility of Al adatoms with increasing temperature, the nucleation sites
decrease and the subsequent grain size increases, leading to the achievement of atomically flat AlN epilayers with good crystal
quality for the nucleation layer grown at 570°C. However, at higher nucleation layer growth temperature, the properties of
the AlN epilayers deteriorate due to the possible appearance of misaligned AlN grains. A model is also developed according
to all observations. 相似文献
20.
We have utilized a variable energy positron beam and infrared transmission spectroscopy to study defects in GaAs epilayers
grown at low temperatures (LT-GaAs) by molecular beam epitaxy. We have measured the Doppler broadening of the positron-electron
annihilation gamma ray spectra as a function of positron implantation energy. From these measurements, we have obtained results
for the depth profiles of Ga monovacancies in unannealed LT-GaAs and Ga monovacancies and arsenic cluster related defects
in annealed LT-GaAs. We have also studied the effects of the Si impurities in annealed LT-GaAs. The infrared transmission
measurements on unannealed LT-GaAs furnish a broad defect band, related to As antisites, centered at 0.370 eV below the conduction
band. 相似文献