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1.
SiGe-on-Insulator (SGOI) is an ideal substrate material for realizing strained-silicon structures that are very competing and popular in present silicon technology. In this paper, two methods are proposed to fabricate SGOI novel structure. One is modified Separation by Implantation of Oxygen (SIMOX) starting from pseuodomorphic SiGe thin film without graded SiGe buffer layer. Results show that two-step annealing can improve the cystallinity quality of SiGe and block the Ge diffusion in high temperature annealing. SGOI structure with good quality has been obtained through two-step annealing. The second method is proposed to achieve SGOI with high content of Ge. High quality strained relax SiGe is grown on a compliant silicon-on-insulator (SOI) substrate by UHCVD firstly. During high temperature oxidation,Ge atoms diffuse into the top Si layer of SOI. We successfully obtain SGOI with the Ge content of 38%, which is available for the growth of strained Si. 相似文献
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In the ternary system Al-Ge-Si, the binary eutectic reactions, L (liquid) ⇔ (Al) + (Si) and L ⇔ (Al) + (Ge) are connected
by a monovariant valley, L ⇔ (Al) + (SiGe), falling from 578 °C at 12.7 wt pct Si to 424 °C at 53 wt pct Ge. The binary, solid
eutectic surface extends from the Al corner of the ternary phase diagram (1.65 wt pct Si to 5.2 wt pct Ge) across to the continuous
(SiGe) solid solution which contains very little Al: several tie triangles, L-(A1)-(SiGe), have been determined using thermal
analysis and electron microprobe analysis (EMPA). Optical and scanning electron microscopy (SEM) examination reveals that
coring in the normal (SiGe) phase is discontinuous, showing composition banding, which indicates that stationary 111 facets
of the solid solution were exposed to the liquid for extended periods up to 500 seconds; details of this interrupted coring
were quantified by EMPA. Similar, smaller, and more gradual variations could also be detected in the (Al) matrix, and these
compositional fluctuations are considered to reflect discontinuities in the local eutectic growth rates. Modification and
twin-ning, induced by Na, are observed in both Al-Si and Al-Ge but decrease progressively with Ge content; coring in the modified
ternary alloys is more continuous. 相似文献
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The strained Si grown on the relaxed SiGe-on-insulator C-MOSFET's is a promising device for the future system LSI devices with the design rule of sub-micron. The achievement of the discrete Ge mole fraction in the SiGe layer is a key engineering in low-temperature SiGe epitaxial growth using HVCVD. The pre-flow of GeH4 gas enhanced the Ge mole fraction and SiGe layer thickness. In addition, the Ge mole fraction and SiGe layer thickness increases with the gas ratio of GeH4/SiH4 + GeH4, process temperature, and gas flow time. However, the haze was produced if the Ge mole fraction is above 22wt%. The discrete-like Ge mole fraction with 22 wt% in 10 nm SiGe layer was obtained by the pre-flow of GeH4 for 10 s, the mixture gas ratio of GeH4/SiH4 + GeH4 of 67%, and the gas flow time for 150 s at the process temperature of 550 C. 相似文献
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HUANG Wentao Shen Guanhao Li Xiyou CHEN Changchun Zhang Wei Liu Zhihong CHEN Peiyi TSIEN Peihsin 《中国稀土学报(英文版)》2004,22(Z2)
Low-temperature-epitaxy n-type silicon layers were grown on arsenic-doped n -type silicon substrate by using ultra-high vacuum chemical vapor deposition (UHV/CVD). The transition region thickness of the Si layers grown under different PH3 flux and different growth temperature were investigated by spreading resistance probe. Results showed that the growth temperature had remarkable influence on the arsenic diffusion from the Si substrate. The thicknesses of the transition region were 0.16 μm grown at 700 ℃ and 0.06 μm grown at 500 ℃, respectively. Moreover, the dopant profiles were very abrupt. X-ray diffraction investigation of the epitaxial Si layer showed the quality of Si layer was very high.SiG e HBT device was fabricated by using a revised double-mesa polysilicon-emitter process. Tests show that the CB-junction breakdown characteristic of the SiGe HBT is very hard, and the leakage current is only 0.3 μA under a reverse voltage of - 14.0 V. The SiGe HBT device had also good output performance, and the current gain is 60. 相似文献
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The synchrotron X-ray double-crystal topography was employed to investigate the structure of Si/SiGe/Si deposited on SIMOX SOI. Rocking curves with three diffraction peaks were acquired before and after 180° rotation of samples. Double-crystal topographs taken at the full width at half maximum (FWHM) of the three peaks differ from each other. Many defects appear in the Si layers that are likely related to the tilt between SOI and epitaxial layers. 相似文献
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通过X射线衍射分析(XRD)和振动磁强计(VSM)磁性测量,研究了替代元素Ti替代Fe元素含量的MnFe1-xTixP0.63Ge0.12Si0.25(x=0,0.01,0.02,0.03)系列化合物的物相结构与磁热效应的影响。结果表明:该系列化合物的结构为Fe2P型六角晶系结构,空间群为P62m。主相均为(Mn,Fe)2(P,Ge,Si),并含有少量的第二相(Mn,Fe)3Si相。随着Ti原子替代Fe原子的增加化合物的晶格常数a增大,晶格常数c略有减小,晶胞体积V基本保持不变。随着Ti含量增加居里温度(TC)减小,热滞ΔThys的大小改进不太明显。MnFeP0.63Ge0.12Si0.25的TC为305 K,当外磁场变化为0~1.5 T时最大磁熵变的绝对值为14.8 J.(kg.K)-1。 相似文献
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Inviewofenergysavingandenvironmentalpro tection ,magneticrefrigerationnearroomtemperaturehasastrongimpactonconventionalgascompressiontechnology .However ,coolingefficiencyofthesystemformagneticrefrigerationismainlydecidedbythemagnitudeofmagnetocaloriceffectformagneticrefrig eratingmaterialsinthesystemunderacertainmagnet icfieldchange .Therefore ,developmentofnewrefrig eratingmaterialswithgreatmagnetocaloriceffectnearroomtemperatureisespeciallyimportant .Therearetwoparameterswhichareusedtochara… 相似文献
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The magneto-caloric effect of Gd5 Si2Ge2 compounds produced by various techniques is investigated in terms of their magnetization behaviors in the magnetic field from 0 to 2.0 T.The studied materials include arc-melted, annealed and sintered alloys.The results demonstrate that the Gd5Si2Ge2 alloys obtained under different processing conditions possess distinct magneto-caloric effect due to their various microstructures.Proper annealing treatment can enhance the magneto-caloric effect of the alloy remarkably.While the sintered alloy bears relatively lower value of magnetic entropy change ( △ SM) than arc-melted one.The magnetic entropy change of the annealed Gd5 Si2Ge2 alloy arrives the arrives the maximum value of - △SM = 15.29 J· kg-1· K-1 for magnetic field change under 2.0 T in the present work. 相似文献
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E.Yüzüak 《中国稀土学报(英文版)》2010,28(3):477-480
The influence of the manganese-alloying on the structure and magnetocaloric properties of the Gd5Si2.05Ge1.95 compound was studied by X-ray powder diffraction and magnetization measurements.The Gd5Si2.05-xGe1.95-xMn2x(2x=0,0.03 and 0.08) compounds crystallized in the Gd5Si2Ge2-type monoclinic structure.In all X-ray powder diffraction patterns,a minor hexagonal Gd5Si3 phase was observed as a second phase.With increasing Mn content,the unit cell volume increased.For the compounds with x=0,0.03 and 0.08,the fi... 相似文献
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V. Radmilovic A. J. Tolley U. Dahmen J. W. MorrisJr. D. Mitlin 《Metallurgical and Materials Transactions A》2003,34(3):543-551
The present work addresses the response of Si-Ge precipitates in Al-0.5Si-0.5Ge (at. pct) to thermalcycling treatments of
the sort known to refine the shapes of Ge precipitates in binary Al-Ge alloys. Alloys aged at 250 °C contained both small,
platelet precipitates on {111} planes and larger, equiaxed precipitates that were heavily twinned. Thermal cycling between
250 °C and 360 °C led to partial or complete dissolution of the platelets. However, the equiaxed particles coarsened at an
essentially constant shape; the shape refinement that led to untwinned, single-variant octahedral precipitates in binary Al-Ge
did not occur. The apparent reason is the heavy twinning of the Si-Ge precipitates, which produces particles with a nearly
spherical shape and rounded, incoherent interfaces and is, hence, a viable mechanism for relaxing the large misfit strain
of the precipitate structure. The twinned particles undergo normal coarsening at an essentially constant shape. After thermal
cycling, the precipitates contain Si and Ge in the approximate ratio of 70Si-30Ge, which is in the composition range expected
for the cycling temperature. 相似文献
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While liquid-state 29Si NMR of phosphorus-bearing organosilicon compounds with more than one phosphorus per molecule can take advantage of the presence of J-coupling nJ(31P29Si) for purposes of structural assignment from J-coupling patterns, conventional 29Si CP/MAS spectra of such molecular solids do not reveal structural details in a straightforward manner. For such compounds it is necessary to obtain 29Si CP/MAS spectra under conditions of simultaneous 1H- and 31P-high power decoupling in order to derive reliable 29Si chemical shift information. 29Si CP/MAS NMR spectra, obtained with and without 31P high power decoupling during the acquisition time, of several organosilicon compounds containing SixPy (x = 1-10, y = 1-10) moieties are reported. 相似文献
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《中国稀土学报(英文版)》2016,(12)
A novel red-emitting K_2(Ge,Si)F_6:Mn~(4+) phosphor with uniform morphology was synthesized by co-precipitation method. The pure K_2GeF_6 phase with P63 mc space group other than P3m1 space group was affirmed just by incorporation of Si in K_2GeF_6 at room temperature according to XRD characterization. SEM images showed lamellar and octahedron grain morphology for K_2GeF_6:Mn~(4+) and K_2(Ge,Si)F_6:Mn~(4+) phosphors, respectively. It was also found that the photoluminescence excitation(PLE) and photoluminescence(PL) showed slight displacement in K_2GeF_6:Mn~(4+) and K_2(Ge,Si)F_6:Mn~(4+) system. And the zero-phonon line(ZPL) of the PL spectrum of K_2GeF_6:Mn~(4+) with Si showed a strong peak. Meanwhile crystalline field surrounding Mn~(4+) changes could affect the decay time in this fluoride system. The color gamut of the LED devices based on K_2(Ge,Si)F_6:Mn~(4+) and K_2GeF_6:Mn~(4+) reached up to 94.58% NTSC(National Television Standards Committee) and 94.386% NTSC, respectively, that was much higher than that based on nitride red phosphors. All these original characteristics in K_2(Ge,Si)F_6:Mn~(4+) phosphor are desirable for potential applications as a red phosphor for improving lighting and display quality of conventional white LEDs. 相似文献
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Amorphous La2Hf2O7 thin films were deposited on Si(100) substrate by pulsed laser deposition (PLD) method under different con-ditions. The interfacial states of the La2Hf2O7/Si films were studied by synchrotron X-ray reflectivity (XRR) and X-ray photoelectron spec-troscopy (XPS). When grown under vacuum condition, silicate, silicide and few SiOx were formed in the interface layer. However, the Hf-silicide formation could be effectively eliminated by the ambient oxygen pressure during film growth. The result revealed that the La2Hf2O7/Si interlayer was intimately related with growth condition. Insufficient supply of oxygen would cause Hf-silicide formation at the interface and it could be most effectively controlled by the ambient oxygen pressure during film growth. 相似文献
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Jun-feng Zhao Shan-guang Liu Xiao-guang Yuan Jian-fei Sun Hong-jun Huang Fu-yang Cao Hong-xian Shen Yu-long Wang 《钢铁研究学报(英文版)》2017,24(4)
The Al22Si/ZL102 bimetal was designed and prepared by extrusion at near-eutectic temperature.The properties and fracture behaviors of different surface treatments between oxide film and zinc coating were compared between the Al22Si and ZL102 bimetal.The average bonding strength of bimetal with intermittent oxide film interface was about 89.3 MPa, which is higher than that of the bimetal fabrica-ted by zinc coating method (about 76.3 MPa).During the process of extrusion, the oxidation film was extruded to crush and the metal was extruded through the micro-cracks of the oxidation film, then the two surfaces were joined together.Altogether, the results showed that extrusion at near-eutectic tem-perature is favorable for achieving a high-quality metallurgical bonded interface. 相似文献
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The effect of Si on the high temperature oxidation behavior of the 30Cr13 martensitic stainless steels was investigated.The underlying mechanism was further discussed by oxidation kinetics curves, scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis.It was ob-served that the addition of Si can significantly reduce the mass gain per unit area and the oxidation rate of the experimental steels.With the increase of Si content, the film surface composed of the wheat-like oxides turned into the small granular oxides after oxidation for 120 h.The SiO2 film formed on the metal substrate inhibited the outward diffusion of the metal cation and the inward diffusion of the oxygen anion; thus, the high temperature oxidation resistance was enhanced. 相似文献
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