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硅分子束外延中硼δ掺杂生长研究 总被引:3,自引:0,他引:3
利用硅分子束外延技术和B2O3掺杂源,成功地实现了硅中的硼δ掺杂,硼δ掺杂面密度NB可达3.4e14cm-2(1/2单层)以上,透射电镜所示宽度为1.5nm.我们首次用原位俄歇电子能谱(AES)对硼在Si(100)表面上的δ掺杂行为进行了初步的研究,发现在NB<3.4e14cm-2时,硼δ掺杂面密度与时间成正比,衬底温度650℃,掺杂源温度9000℃时,粘附速率为4.4e13cm-2/min;在NB>3.4e14cm-2时,粘附有饱和趋势,测量表明在硼δ掺杂面密度NB高达4.4e14c 相似文献
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InSb材料由于其优异的光电性能,一直是军事领域重要的红外探测器材料。而高温工作是InSb发展的一个重要方向,开发分子束外延InSb材料是实现高温工作的基础。本文采用分子束外延工艺生长获得了高质量的InSb薄膜,通过金相显微镜、X射线双晶衍射仪、原子力显微镜、SEM和EDX等检测手段对InSb外延膜进行表面缺陷、晶体质量表征和分析,并采用标准的InSb器件工艺制备128×128焦平面探测器芯片进行材料的验证,结果表明该材料性能可以满足制备高性能器件的要求。 相似文献
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报道了用 MBE方法生长掺 In的 n型 Hg Cd Te材料的研究结果 .发现 In作为 n型施主在 Hg Cd Te中电学激活率接近 10 0 % ,其施主电离激活能至少小于 0 .6 m e V.确认了在制备红外焦平面探测器时有必要将掺杂浓度控制在~ 3× 10 1 5 cm- 3水平 .比较了高温退火前后 In在 Hg Cd Te中的扩散行为 ,得出在 40 0℃温度下 In的扩散系数约为10 - 1 4 cm2 / s,并确认了 In原子作为 Hg Cd Te材料的 n型掺杂剂的可用性和有效性 . 相似文献
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利用分子束外延(Molecular Beam Epitaxy, MBE)系统生长了In掺杂硅基碲镉汞(Mercury Cadmium Telluride, MCT)材料。通过控制In源温度获得了不同掺杂水平的高质量MCT外延片。二次离子质谱仪(Secondary Ion Mass Spectrometer, SIMS)测试结果表明,In掺杂浓度在1×1015~2×1016 cm-3之间。表征了不同In掺杂浓度对MCT外延层位错的影响。发现位错腐蚀坑形态以三角形为主(沿<■>方向排列),且位错密度与未掺杂样品基本相当。对不同In掺杂浓度的材料进行汞饱和低温处理后,样品的电学性能均有所改善。结果表明,In掺杂能够提高材料的均匀性,从而获得较高的电子迁移率。 相似文献
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N-type ZnSe with electron concentration up to 3 × 1020 cm−3 and low resistivity down to 1 × 10−4 ohm-cm, has been grown using a selective doping technique with chlorine during molecular beam epitaxy. The photoluminescence
evaluation shows that the selectively doped ZnSe layers are superior to uniformly doped ones, especially for the case of high-concentration
chlorine doping. The in-depth profile of chlorine concentration in a selectively doped sample was measured with secondary-ion
mass spectroscopy (SIMS). The SIMS analysis shows only slight diffusion of the incorporated chlorine atoms even in highly
doped samples. 相似文献
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B. L. Vanmil A. J. Ptak L. Bai Lijun Wang M. Chirila N. C. Giles T. H. Myers Larry Wang 《Journal of Electronic Materials》2002,31(7):770-775
Epitaxial ZnSe layers were grown by molecular beam epitaxy (MBE) to study Cr incorporation with the long-term goal of demonstrating
an alternate route for achieving transition-metal-doped lasers. Concentrations between 1015 atoms cm−3 and 4×1020 atoms cm−3 were achieved. Secondary ion-mass spectroscopy (SIMS) concentration profiles strongly suggest that surface segregation and
accumulation of Cr occurs during growth. Photoluminescence (PL) measurements indicate Cr is incorporated in the optically
active Cr2+ state up to levels of ∼1019 cm−3. Electron paramagnetic resonance (EPR) studies suggest that the Cr atoms exhibit collective magnetic behavior even at these
levels. X-ray diffraction (XRD) and reflection high-energy electron diffraction (RHEED) indicate high structural quality is
maintained for Cr incorporation for levels up to ∼1019 atoms cm−3. 相似文献
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P. S. Wijewarnasuriya M. D. Langer S. Sivananthan J. P. Faurie 《Journal of Electronic Materials》1995,24(9):1211-1218
We report the results of the transport properties and the recombination mechanisms of indium-doped HgCdTe(211)B (x ≈ 23.0%
± 2.0%) layers grown by molecular beam epitaxy. We have investigated the origin(s) of the background doping limitation in
these layers. Molecular beam epitaxially grown layers exhibit excellent Hall characteristics down to indium levels of 2 x
1015 cm−3. Electron mobilities ranging from (2-3) x 105 cm2/v-s at 23K were obtained. Measured lifetime data fits very well with the intrinsic band-to-band recombinations. However,
below 2 x 1015 cm−3 doping levels, mobility vs temperature curves starts to reflect nonuniformity in carrier distribution. Also, when we reduced
the Hg vacancy concentration down to 1012 cm−3 range, by annealing at 150°C, Hall characteristics shows an increase in the nonuniformity in the epilayers. It was found
that after annealed at 150°C, the obtained SR defect level has a different origin than the previously obtain Hg-vacancy related
defect level. 相似文献
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We report on the realization of a modified delta doping technique to obtain doping profiles in MBE grown GaAs, measured by capacitance-voltage (C-V) methods with full-widths at half-maximum (FWHM)s of 25 ± 5Å and peak concentrations of up to 1.1 × 1019 cm?3. In this modified delta doping technique, both the Ga and Si shutters were opened for 15 sec during the delta doped layer growth while only the Si shutter is opened during conventional delta doping. Comparison of the two techniques under the same dopant flux and shutter-open-time interval shows that higher sheet-carrier concentrations with narrower FWHMs and higher peak concentrations are obtained with the modified delta doping than with the conventional delta doping method. This suggests that Si donor incorporation is enhanced by the Ga adatoms while broadening of the Si donor distribution is still negligible for this short time interval. The effects of the substrate temperature and the shutter-open time on the Si donor distribution have also been investigated. 相似文献
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M. A. Sánchez-García E. Calleja F. J. Sanchez F. Calle E. Monroy D. Basak E. Muñoz C. Villar A. Sanz-Hervas M. Aguilar J. J. Serrano J. M. Blanco 《Journal of Electronic Materials》1998,27(4):276-281
GaN layers have been grown by plasma-assisted molecular beam epitaxy on AlN-buffered Si(111) substrates. An initial Al coverage
of the Si substrate of aproximately 3 nm lead to the best AlN layers in terms of x-ray diffraction data, with values of full-width
at half-maximum down to 10 arcmin. A (2×2) surface reconstruction of the AlN layer can be observed when growing under stoichiometry
conditions and for substrate temperatures up to 850°C. Atomic force microscopy reveals that an optimal roughness of 4.6 nm
is obtained for AlN layers grown at 850°C. Optimization in the subsequent growth of the GaN determined that a reduced growth
rate at the beginning of the growth favors the coalescence of the grains on the surface and improves the optical quality of
the film. Following this procedure, an optimum x-ray full-width at half-maximum value of 8.5 arcmin for the GaN layer was
obtained. Si-doped GaN layers were grown with doping concentrations up to 1.7×1019 cm−3 and mobilities approximately 100 cm2/V s. Secondary ion mass spectroscopy measurements of Be-doped GaN films indicate that Be is incorporated in the film covering
more than two orders of magnitude by increasing the Be-cell temperature. Optical activation energy of Be acceptors between
90 and 100 meV was derived from photoluminescence experiments. 相似文献
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C. A. Coronado E. Ho P. A. Fisher J. L. House K. Lu G. S. Petrich L. A. Kolodziejski 《Journal of Electronic Materials》1994,23(3):269-273
The use of gas source molecular beam epitaxy, using hydrogen selenide and elemental Zn as source materials, has resulted in
the growth of high quality ZnSe on closely lattice-matched GaAs and (In,Ga)P. The undoped ZnSe epilayers are comparable in
quality to material grown by molecular beam epitaxy, as indicated by narrow double-crystal x-ray diffraction rocking curves
and intense photoluminescence dominated by a single donor-bound near-bandedge excitonic feature. Nitrogen species, derived
from a radio frequency plasma source, are successfully used as acceptor impurities for ZnSe; photoluminescence spectra confirm
the incorporation of nitrogen by the presence of the expected donor-to-acceptor pair recombination. Atomic concentrations
of nitrogen as high as 5 x 1018 cm-3, are measured by secondary ion mass spectroscopy. Thus far, capacitance-voltage measurements indicate net acceptor concentrations
(NA -ND) of approximately 1017 cm-3. 相似文献
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We report the molecular beam epitaxial growth of InSb quantum dots (QD) inserted as sub-monolayers in an InAs matrix which exhibit intense mid-infrared photoluminescence up to room temperature. The InSb QD sheets were formed by briefly exposing the surface to an antimony flux (Sb2) exploiting an As-Sb anion exchange reaction. Light emitting diodes were fabricated using 10 InSb QD sheets and were found to exhibit bright electroluminescence with a single peak at 3.8 μm at room temperature. 相似文献
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S. H. Li P. K. Bhattacharya S. W. Chung J. X. Zhou E. Gulari 《Journal of Electronic Materials》1993,22(4):409-412
Solid boron and antimony doping of silicon and SiGe grown by molecular beam epitaxy using disilane and germane as sources
has been studied. Elemental boron is a well behaved p-type dopant. At effusion cell temperatures of 1700–1750°C, hole carrier
concentrations in the 1020 cm−3 range have been obtained. Elemental antimony doping shows surface segregation problems. For uniformly doped layers, the as-grown
materials do not show n-type conductivity. Electron concentrations in the 1017 cm−3 range were obtained by post-growth conventional and rapid thermal annealing at 900 and 1000°C, respectively. The electron
Hall mobility improves with optimum annealing time. Delta doping of buried layers exhibits slightly better incorporation behavior
including significant surface riding effects. 相似文献
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Capacitance and Hall effect measurements in the temperature range 10-300 K were performed to evaluate the deep and shallow
level characteristics of Si-doped n-AlxGa-xAs layers with 0 × 0.4 grown by molecular beam epitaxy. For alloy compositions × 0.3 the overall trap concentration was found
to be less than 10−2 of the carrier concentration. In this composition range the transport properties of the ternary alloy are comparable to those
of n-GaAs:Si except for lower electron mobibities due to alloy scattering. With higher Al content one dominant electron trap
determines the overall electrical properties of the material, and in n-Al0.35Ga0.65As:Si the deep trap concentration is already of the order of the free-carrier concentration or even higher. For the composition
× = 0.35 ± 0.02 the influence of growth temperature and of Si dopant flux intensity on the deep trap concentration, on shallow
and deep level activation energy, and on carrier freeze-out behaviour was studied and analyzed in detail. Our admittance measurements
clearly revealed that the previously assumed deepening of the shallow level in n-Alx Ga1-x As of alloy composition close to the direct-indirect cross-over point does actuallynot exist. In this composition range an increase of the Si dopant flux leads to a reduction of the thermal activation energy
for electron emission from shallow levels due to a lowering of the emission barrier by the electric field of the impurities.
The increasing doping flux also enhances the concentration of the dominant electron trap strongly, thus indicating a participation
of the dopant atoms in the formation of deep donor-type (D,X) centers. These results are in excellent agreement with the model
first proposed by Lang et al. for interpretation of deep electron traps in n-Alx Ga1-x grown by liquid phase epitaxy. 相似文献