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1.
Si1−xGex/Si heterostructures play a primary role in the Si-based fast electronics developments of today. In this work, we will present the experimental results of infrared spectroscopic ellipsometry (IRSE) for structural determination of the boron heavily doped SiGe/Si sample grown by ultra-high vacuum chemical vapor deposition (UHVCVD) (the Ge atomic percent, the thickness of SiGe film and boron concentration). Especially, the principle of boron concentration in p-type SiGe film layer determined by IRSE was elucidated in detail. In addition, in order to corroborate the validity of IRSE for determining dopant concentration, secondary ion mass spectroscopy (SIMS) experiment has also been carried out. The close experimental agreement between IRSE and SIMS demonstrate that IRSE as a contactless, and non-destructive technology can be used in-line tools in production used for measuring the Ge content, the thickness of SiGe layer and boron concentration in p-type dopant SiGe/Si heterostructure, which often used the base layer of SiGe hetero-junction bipolar transistor (HBT) devices. 相似文献
2.
本文基于费米黄金法则和波尔兹曼碰撞项近似理论,对Si基应变材料各空穴散射机率与应力强度、晶向的关系进行了深入的研究。结果表明:1)在应力的作用下,Si基应变材料总散射几率明显降低;2)当Ge组分为0.2时,总散射几率量化排序为应变Si/(111)Si1-xGex>应变Si/(101)Si1-xGex>应变Si1-xGex/(111)Si>应变Si1-xGex/(101)Si>应变Si/(001)Si1-xGex>应变Si1-xGex/(001)Si;3)应力作用下空穴声学声子散射几率的降低是引起Si基应变材料总散射几率降低的主要原因。本文量化结论可为Si基应变及其他应变材料的相关研究提供重要理论参考。 相似文献
3.
M. Bargallo Gonzalez E. Simoen N. Naka Y. Okuno G. Eneman A. Hikavyy P. Verheyen R. Loo C. Claeys V. Machkaoutsan P. Tomasini S.G. Thomas J.P. Lu R. Wise 《Materials Science in Semiconductor Processing》2008,11(5-6):285
The purpose of this paper is to evaluate the impact of the geometry of embedded Si1−xGex source/drain junctions on the stress field. Stress simulations were performed using TSUPREM4 2D software to further investigate the elastic strain relaxation as a function of Si1−xGex alloy active size, in the regime where no plastic relaxation is present. Moreover, the role of the epilayer thickness and the Ge content on the stress levels is also discussed. The work is complemented with experimental Raman spectroscopy. 相似文献
4.
N. V. Vostokov Yu. N. Drozdov Z. F. Krasil’nik O. A. Kuznetsov D. N. Lobanov A. V. Novikov M. V. Shaleev 《Semiconductors》2006,40(2):229-233
The results of studying the growth of self-assembled Ge(Si) islands on relaxed Si1?xGex/Si(001) buffer layers (x≈25%), with a low surface roughness are reported. It is shown that the growth of self-assembled islands on the buffer SiGe layers is qualitatively similar to the growth of islands on the Si (001) surface. It is found that a variation in the surface morphology (the transition from dome-to hut-shaped islands) in the case of island growth on the relaxed SiGe buffer layers occurs at a higher temperature than for the Ge(Si)/Si(001) islands. This effect can be caused by both a lesser mismatch between the crystal lattices of an island and the buffer layer and a somewhat higher surface density of islands, when they are grown on an SiGe buffer layer. 相似文献
5.
R. Kube H. Bracht J. Lundsgaard Hansen A. Nylandsted Larsen E.E. Haller S. Paul W. Lerch 《Materials Science in Semiconductor Processing》2008,11(5-6):378
Experiments on the diffusion of Si and Ge in Si1-xGex-isotope heterostructures with Ge contents x=0, 0.05, and 0.25 were performed at temperatures between 870 and . The concentration profiles of the stable Si- and Ge-isotopes were recorded by means of time-of-flight secondary ion mass spectrometry. For all compositions, an Arrhenius type temperature dependence of diffusion was observed. The activation enthalpy of Si diffusion in SiGe equals the activation enthalpy of Ge diffusion and the pre-exponential factors agree within experimental accuracy. However, the absolute values of the Si and Ge diffusion coefficients indicate a clear trend. In elemental Si the diffusion coefficients of Si and Ge agree, but the difference between the diffusion coefficients of Ge and Si in Si1-xGex increases with x. This indicates that with increasing Ge content the diffusional jumps of Ge atoms become more successful compared to that of Si. This trend is explained with an increasing contribution of vacancies to self-diffusion in Si1-xGex with an increase of the Ge content x. 相似文献
6.
Grekhov I. V. Kostina L. S. Argunova T. S. Belyakova E. I. Rozkov A. V. Shmidt N. M. Yusupova Sh. A. Je J. H. 《Semiconductors》2010,44(8):1101-1105
A new method for fabricating SiGe-on-insulator substrates, i.e., direct bonding of thermally oxidized Si wafers with Si1 − x
Ge
x
wafers cut from Czochralski-grown crystals, is suggested. Si1 − x
Ge
x
layers no larger than 10 μm thick in SiGe/SiO2/Si compositions were fabricated by chemical mechanical polishing. To increase the Ge content in the Si1 − x
Ge
x
layer, thermal oxidation was used. It was shown that the increase in the Ge content and heat treatment procedures at 1250°C
are not accompanied by degradation of structural and electrical characteristics of Si1 − x
Ge
x
layers. 相似文献
7.
N. V. Vostokov Yu. N. Drozdov Z. F. Krasil’nik O. A. Kuznetsov A. V. Novikov V. A. Perevoshchikov M. V. Shaleev 《Russian Microelectronics》2005,34(4):203-209
The results are presented of the fabrication of strain-relaxed graded Si1 − x
Gex/Si(001) buffer layers with a maximum Ge fraction of about 0.25 that have a low density of threading dislocations (<106 cm−2) and low surface roughness. The buffer layers are grown by atmospheric-pressure hydride CVD. It is found that chemical mechanical polishing can reduce their surface roughness to a level comparable with that of the original Si(001) substrates. It is shown that the polished buffer layers can serve as substrates for MBE-grown SiGe/Si heterostructures.__________Translated from Mikroelektronika, Vol. 34, No. 4, 2005, pp. 243–250.Original Russian Text Copyright © 2005 by Vostokov, Drozdov, Krasil’nik, Kuznetsov, Novikov, Perevoshchikov, Shaleev. 相似文献
8.
Kyu-Hwan Shim Hyeon Deok Yang Yeon-Ho Kil Jong-Han Yang Woong-Ki Hong Jeong-Jin Kim Sukill Kang Tae Soo Jeong Taek Sung Kim 《Materials Science in Semiconductor Processing》2013,16(1):126-130
We have investigated the Si0.8Ge0.2/Si multi-layer grown directly onto the Si (001) substrates using reduced pressure chemical vapor deposition. The thicknesses of the Si0.8Ge0.2/Si multi-layer were determined using transmission electron microscopy. From the results of energy-dispersive X-ray spectroscopy and X-ray diffraction analyses on the Si0.8Ge0.2/Si multi-layer, Ge composition in the Si1?xGex layers was determined as ~20% and the value of residual strain ε of the Si0.8Ge0.2 layer is calculated to be 0.012. Three peaks are observed in Raman spectrum, which are located at approximately 514, 404, and 303 cm?1, corresponding to the vibration of Si–Si, Si–Ge, and Ge–Ge phonons, respectively. The photoluminescence spectrum originates from the radiative recombinations both from the Si substrate and the Si0.8Ge0.2/Si multi-layer. For the Si0.8Ge0.2/Si multi-layer, the transition peaks related to the quantum well region observed in the photocurrent spectrum were preliminarily assigned to e–hh and e–lh fundamental excitonic transitions. 相似文献
9.
F. F. Sizov V. P. Klad’ko S. V. Plyatsko A. P. Shevlyakov Yu. N. Kozyrev V. M. Ogenko 《Semiconductors》1997,31(8):786-788
Si, Ge, and Si1−x
Gex epitaxial layers and Si/Si1−x
Gex superlattices have been obtained on (100) and (111) silicon substrates by molecular-beam epitaxy. The growth processes and
the structural characteristics and chemical composition of the structures were studied by x-ray diffraction and Auger spectroscopy.
It is shown that under the experimental conditions for obtaining Si/Si1−x
Gex superlattices structurally perfect, strained superlattices with satellites up to ±5 orders can be obtained.
Fiz. Tekh. Poluprovodn. 31, 922–925 (August 1997) 相似文献
10.
G. Bremond A. Souifi O. De Baeros A. Benmansour F. Ducroquet P. Warren D. Dutartre 《Journal of Electronic Materials》1996,25(7):1023-1027
Relaxed Si1−xGex layers grown by rapid thermal chemical vapor deposition (RTCVD) have been characterized by photoluminescence (PL) spectroscopy.
The structures consist of a Si1−xGex capping layer with a 0.32 and 0.52 Ge concentration, grown on a compositionally graded Si1−xGex buffer layer. The effect of the composition grading rate on the layer quality has been intensively studied. Well-resolved
near band edge luminescence (excitonic lines with no-phonon and phonon replica similar as in bulk SiGe alloys) coming from
the relaxed alloy capping layer and dislocation-related bands (Dl, D2, D3, D4 lines) in the graded buffer layer have been
measured. The electronic quality of this relaxed capping layer, controlled by the design of the compositionally graded buffer
layer, has been determined by the excitonic photoluminescence. A detailed analysis of the energy of the D4 dislocation band
demonstrates that the main misfit dislocations remain confined in the first steps of the graded buffer layer. Si1−xGex layers grown on these pseudo-substrates either under compressive or tensile strain and the well-defined PL results obtained
are discussed on the bases of strain symmetrization and of high quality of the layers. This points out the possibility of
using such high quality relaxed Si1−xGex layers as substrates for the integration of new devices associated with Si technology. 相似文献
11.
A simple technique leading to the measurement of minority carrier lifetimes of UHV compatible LPCVD Si and SiGe by C–t depth profiling of Metal:Oxide:Si:SiGe:Si structures is reported. A high quality gate oxide is realised by low temperature (<100°C) plasma anodisation thereby reducing any oxidation effects on the underlying epitaxial layer quality. Capacitance response times were observed for an impurity concentration of 2.5×1017 cm−3, giving rise to generation lifetimes of the Si and Si0.9Ge0.1 of >0.55 and 2.6 μs respectively, reflective of very high quality epitaxial semiconductor material. 相似文献
12.
Silicon (Si) and Si with a 60 nm Si0.95Ge0.05 epilayer cap (Si0.95Ge0.05/Si) were implanted with 60 keV, 1×1013 cm−2 boron (B) followed by annealing in nitrogen (N2) or dry oxygen (O2) in two different anneal conditions. B+implantation energy and dose were set such that the B peak is placed inside Si in Si0.95Ge0.05/Si samples and concentration independent B diffusion is achieved upon annealing. For samples annealed above 1075 °C, Ge diffusing from the Si0.95Ge0.05 epilayer cap in Si0.95Ge0.05/Si samples reached the B layer inside Si and resulted in retarded B diffusion compared to the Si samples. For annealing done at lower temperatures, diffusion of Ge from Si0.95Ge0.05 epilayer cap does not reach the B layer inside Si. Thus B diffusion profiles in the Si and Si0.95Ge0.05/Si samples appear to be similar. B diffusion in dry oxidizing ambient annealing of Si0.95Ge0.05/Si samples further depends on the nature of Si0.95Ge0.05 oxidation which is set by the duration and the thermal budget of the oxidizing anneal. 相似文献
13.
W. Feng W. K. Choi L. K. Bera M. Ji C. Y. Yang 《Materials Science in Semiconductor Processing》2001,4(6)
The optical properties of as-prepared and rapid thermal oxidized (RTO) heteroepitaxial Si1−x−yGexCy alloys grown on Si substrate have been characterized using spectroscopic ellipsometry. The critical points E1, E0′, E2 band gaps were determined by line shape fitting in the second derivative spectra of the pseudo-dielectric functions. For as-prepared films, the E1 gap increases with C concentration and a linear dependence on C content was observed. However, the E2 gap decreases as the C concentration increases. For the RTO samples, the amplitude of E2 transition reduces rapidly and the E1 transition shifts to a lower energy. The reduction in the amplitude of E2 transitions is due to the presence of oxide layer. A high Ge content layer and the low C content in the RTO films account for the E1 shift to lower energy and the increase of the refractive indices. 相似文献
14.
The formation of self-aligned Ti(Si(1−x)Ge(x))2 on submicron lines is described. The silicide/germanide is formed by reacting sputtered Ti with epitaxially grown Si(1−x)Ge(x) of composition and thickness relevant to high mobility Si(1−x)Ge(x) channel field effect transistors. Ti(Si(1−x)Ge(x))2 formation on narrow lines was carried out on phosphorous doped material, because of the well known difficulties of forming
silicide on heavily n-doped silicon. A companion set of boron doped blanket films was also processed. The results show that
the process temperature required for the minimization of silicide/germanide sheet resistance is reduced as compared to silicide
formation on Si alone. However, the silicide/germanide films agglomerate with increased high temperature processing more easily
than pure silicide. The thermal stability is degraded more for films with higher Ge content and is a strong function of dopant
type. Silicide/germanide formation on phosphorous doped Si(1−x)Ge(x) layers with x = 10% have a line width dependence similar to silicide formation. Formation on phosphorous doped Si(1−x)Ge(x) layers with x = 27% display an inverse line width dependence, with higher overall sheet resistance. Formation of silicide/germanide
on blanket films of boron doped Si(1−x)Ge(x) with x = 27% behaved similar to the formation of silicide on silicon. 相似文献
15.
R. Qian B. Anthony T. Hsu J. Irby D. Kinosky S. Banerjee A. Tasch 《Journal of Electronic Materials》1992,21(4):395-399
In this work, remote plasma-enhanced chemical vapor deposition (RPCVD) has been used to grow Ge
x
Si1−x
/Si layers on Si(100) substrates at 450° C. The RPCVD technique, unlike conventional plasma CVD, uses an Ar (or He) plasma
remote from the substrate to indirectly excite the reactant gases (SiH4 and GeH4) and drive the chemical deposition reactions. In situ reflection high energy electron diffraction, selected area diffraction,
and plan-view and cross-sectional transmission electron microscopy (XTEM) were used to confirm the single crystallinity of
these heterostructures, and secondary ion mass spectroscopy was used to verify abrupt transitions in the Ge profile. XTEM
shows very uniform layer thicknesses in the quantum well structures, suggesting a Frank/ van der Merwe 2-D growth mechanism.
The layers were found to be devoid of extended crystal defects such as misfit dislocations, dislocation loops, and stacking
faults, within the TEM detection limits (∼105 dislocations/cm2). Ge
x
Si1−x
/Si epitaxial films with various Ge mole fractions were grown, where the Ge contentx is linearly dependent on the GeH4 partial pressure in the gas phase for at leastx = 0 − 0.3. The incorporation rate of Ge from the gas phase was observed to be slightly higher than that of Si (1.3:1). 相似文献
16.
Mashin A. I. Nezhdanov A. V. Filatov D. O. Isakov M. A. Shengurov V. G. Chalkov V. Yu. Denisov S. A. 《Semiconductors》2010,44(11):1504-1510
The method of confocal Raman microscopy is used for the first time to study the spatial distribution of elemental composition
and elastic strains in self-assembled GexSi1 − x
/Si(001) islands grown by the method of sublimation molecular-beam epitaxy in the GeH4 ambient. The lines related to vibrational modes Si-Si, Ge-Ge, and Si-Ge are identified in the Raman spectra measured in the
regions with dimensions <100 nm on the surface of the samples. The spatial distribution of the Ge atomic fraction x in the Ge
x
Si1 − x
alloy and of the elastic strain ɛ (averaged in depth over the island layer) have been calculated from the maps of the Raman
shifts of the corresponding lines over the sample surface. The dependences of x and ɛ on the islands’ growth temperature and on the nominal thickness of the deposited Ge layer have been studied. 相似文献
17.
《Microelectronics Journal》2007,38(6-7):800-804
The 20-nm-thick Si cap layer/74-nm-thick Si0.72Ge0.28 epilayer/Si heterostructures implanted by 25 keV H+ ion to a dose of 1×1016 cm−2 were annealed in ultra-high vacuum ambient and dry O2 ambient at the temperature of 800 °C for 30 min, respectively. Rutherford backscattering/ion channeling (RBS/C), Raman spectra, high-resolution X-ray diffraction (HRXRD) and atomic force microscopy (AFM) were used to characterize the structural characteristics of the Si0.72Ge0.28 layer. Investigations by RBS/C demonstrated that the crystal quality of the Si/Si0.72Ge0.28/Si heterostructure sample implanted by 25 keV H+ in conjunction with subsequent annealing in dry O2 ambient is superior to that of identical sample annealing in ultra-high vacuum ambient. The less strain relaxation of SiGe layer of the Si/Si0.72Ge0.28/Si heterostructures implanted by H ion and annealed in dry O2 ambient at the temperature of 800 °C for 30 min could be doublechecked by Raman spectra as well as HRXRD, which was compared with that in an identical sample annealed in ultra-high vacuum ambient for identical thermal budget. In addition, the SiGe layer of the H-implanted Si/SiGe/Si heterostructural sample annealed in dry O2 ambient accompanied by better crystal quality and less strain relaxation made its surface morphology superior to that of the sample annealed in ultra-high vacuum ambient at the temperature of 800 °C for 30 min, which was also verified by AFM images. 相似文献
18.
The electrical properties of Ni0.95Pt0.05-germanosilicide/Si1_xGex contacts on heavily doped p-type strained Sil-xGex layers as a function of composition and doping concentration for a given composition have been investigated. A four-terminal Kelvin-resistor structure has been fabricated by using the conventional com- plementary metal-oxide-semiconductor (CMOS) process to measure contact resistance. The results showed that the contact resistance of the Ni0.95Pt0.05-germanosilicide/Sil-xGex contacts slightly reduced with increasing the Ge fraction. The higher the doping concentration, the lower the contact resistivity. The contact resistance of the samples with doping concentration of 4×10^19 cm^-3 is nearly one order of magnitude lower than that of the sam- ples with doping concentration of 5 × 10^17 cm^-3. In addition, the influence of dopant segregation on the contact resistance for the lower doped samples is larger than that for the higher doped samples. 相似文献
19.
Sachin Joshi Sagnik Dey Michelle Chaumont Alan Campion Sanjay K. Banerjee 《Journal of Electronic Materials》2007,36(6):641-647
We demonstrate ultra-thin (<150 nm) Si1−x
Ge
x
dislocation blocking layers on Si substrates used for the fabrication of tensile-strained Si N channel metal oxide semiconductor
(NMOS) and Ge P channel metal oxide semiconductor (PMOS) devices. These layers were grown using ultra high vacuum chemical
vapor deposition (UHVCVD). The Ge mole fraction was varied in rapid, but distinct steps during the epitaxial layer growth.
This results in several Si1−x
Ge
x
interfaces in the epitaxially grown material with significant strain fields at these interfaces. The strain fields enable
a dislocation blocking mechanism at the Si1−x
Ge
x
interfaces on which we were able to deposit very smooth, atomically flat, tensile-strained Si and relaxed Ge layers for the
fabrication of high mobility N and P channel metal oxide semiconductor (MOS) devices, respectively. Both N and P channel metal
oxide semiconductor field effect transister (MOSFETs) were successfully fabricated using high-k dielectric and metal gates
on these layers, demonstrating that this technique of using ultra-thin dislocation blocking layers might be ideal for incorporating
high mobility channel materials in a conventional CMOS process. 相似文献
20.
P. Das Kanungo A. Wolfsteller N.D. Zakharov P. Werner U. Gösele 《Microelectronics Journal》2009,40(3):452-33
Electrical properties of epitaxial single-crystalline Si/SiGe axial heterostructure nanowires (NWs) on Si〈1 1 1〉 substrate were measured by contacting individual NWs with a micro-manipulator inside an scanning electron microscope. The NWs were grown by incorporating compositionally graded Si1−xGex segments of a few nm thicknesses in the Si NWs by molecular beam epitaxy. The I-V characteristics of the Si/SiGe heterostructure NWs showed Ohmic behavior. However, the resistivity of a typical heterostructure NW was found to be significantly low for the carrier concentration extracted from the simulated band diagram. Similarly grown pure Si and Ge NWs showed the same behavior as well, although the I-V curve of a typical Si NW was rectifying in nature instead of Ohmic. It was argued that this enhanced electrical conductivities of the NWs come from the current conduction through their surface states and the Ge or Si/SiGe NWs are more strongly influenced by the surface than the Si ones. 相似文献