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41.
Wenhua SHI Lei ZHAO Liping LUO Qiming WANG 《材料科学技术学报》2007,23(3):301-303
The fluctuations of the strained layer in a superlattice or quantum well can broaden the width of satellite peaks in double crystal X-ray diffraction (DCXRD) pattern. It is found that the width of the 0^th peak is directly proportional to the fluctuation of the strained layer if the other related facts are ignored. By this method, the Ge-Si atomic interdiffusion in Ge nano-dots and wetting layers has been investigated by DCXRD. It is found that thermal annealing can activate Ge-Si atomic interdiffusion and the interdiffusion in the nano-dots area is much stronger than that in the wetting layer area. Therefore the fluctuation of the Ge layer decreases and the distribution of Ge atoms becomes homogeneous in the horizontal Ge (GeSi actually) layer, which make the width of the 0^th peak narrow after annealing. 相似文献
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为了研究器件参数对GeSi MOSFET器件性能的影响,本文在建立一个简单的GeSi MOSFET的器件模型的基础上,对GeSi MOSFET的纵向结构进行了系统的理论分析.确定了纵向结构的CAP层厚度、沟道层载流子面密度、DELTA掺杂浓度以及量子阱阱深之间的关系,得出了阈值电压与DELTA掺杂浓度、栅氧化层厚度及CAP层厚度之间的关系,还得出了栅压与沟道载流子面密度、栅氧化层厚度及CAP层厚度之间的关系.并且在此基础上得出了一些有意义的结果.为了更细致、精确地进行分析,我们分别对GeSi PMOSFET和GeSi NMOSFET在MEDICI上做了模拟. 相似文献
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分析了导模-辐射模耦合理论和利用经塔米尔的传输回路方法论改造过的扰动理论进行解析的结果。根据上述理论对1.3μm GeSi/Si异质结波导光栅耦合器波导层的厚度、槽形、长度、宽度、周期、槽深等做了近似的设计。 相似文献
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采用低温生长缓冲层,高温生长GeSi外延层的方法在n型Si衬底上外延生长(i)Ge0.85Si0.15-(p)Si层,以此材料作为吸收区制备成GeSi/Si异质结pin台面光电二极管。其波长范围为0.7-1.55μm,峰值波长位于1.06μm,暗电流密度低达0.033μA/mm^2(-2V),在1.06μm和1.3μm处的响应度分别为1.8A/W(-2V)和0.066A/W(-V)。 相似文献
45.
在Ge0.05Si0.95/Si脊形光波导的等效模型的耻,利用数字迭代法求解出了平板光波导波导层的有效折射率N1,N2及脊形光波导等效模型的有效折射率N3。从求出的有效折射率来确脊形光流导传输单模光流时要求的内外脊高b和h及脊宽ω,综合考虑得出b=5000mm,h=3500nm,ω=7000nm。从而为脊形光波导的设计提供了有价值的理论依据。 相似文献
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根据半导体理论并结合实验结果,分析了以GeSi/Si超晶格为吸收材料的PIN红外探测器的漏电现象。结果表明:当锗含量x=0.6时,探测器的暗电流密度可达到10-5A/cm2,这是由超晶格的禁带宽度决定的。实际器件的暗电流较大,主要是表面因素和加工工艺的影响。 相似文献
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利用有效折射率法分析了Ge0.05Si0.95/Si脊形光波导的光场分布,得到了这种光波导在传输单模时内脊高b、外脊高h和脊宽W的合理取值,还为其它光波导器件的设计奠定了基础。 相似文献
50.
Electron traps, hole traps, and the dominant recombination-generation (R-G) centers have been investigated with deep level
transient spectroscopy and current-voltage/temperature measurements in heteroepitaxial GexSi1-x alloys with x ranging from 0.15 to 1, grown on graded Gey.Si1−y/Si substrates. For all samples with compositions x < 0.85, which retain the Si-like conduction band structure, we detect
a dominant electron trap and R-G center whose activation energy is ΔE = 0.5 eV, independent of composition. This energy agrees
with that of electron traps previously reported for plastically deformed (PD) Si, suggesting a connection to the Si-like band
structure. This 0.5 eV level dominates the reverse leakage current over a wide range of growth and annealing conditions for
the 30% Ge samples, indicating that the electronic state at ΔE = 0.5 eV is a very efficient R-G center, as would be expected
from its midgap position. Alternatively, for strain relaxed, pure Ge (< 1), we detect electron traps at Ec − 0.42 eV and Ec − 0.28 eV, in agreement with the literature on PD Ge and Ge bicrystals. These energies are significantly different from those
observed for x < 0.85, and we conclude that these changes in activation energy are due to changes in the conduction band structure
for high Ge content. Moreover, in contrast with the Si-like samples (x < 0.85), the reverse leakage current in the relaxed
Ge cap layer is not controlled by deep levels, but is rather dictated by intrinsic, band-to-band generation due to the reduced
bandgap of Ge as compared to Si-like alloys. Only for reverse bias magnitudes which incorporate a significant portion of the
graded buffer within the depletion region do R-G centers dominate the reverse leakage current. These results confirm the high
quality of the strain-relaxed, pure Ge cap region which was grown on a GeySi1−y/Si step graded heterostructure (where y was increased from 0 to 1) by ultra high vacuum chemical vapor deposition. Finally,
we report for the first time, what is apparently the dislocation kink site state at Ec − 0.37 eV, in a GexSi1−x alloy. 相似文献