In Situ Diagnostics of Vuv Laser Cvd of Semiconductor Interfaces by Ftir Spectroscopy and Spectroscopic Ellipsometry

1995 ◽  
Vol 397 ◽  
Author(s):  
M. Barth ◽  
J. Knobloch ◽  
P. Hess
Keyword(s):  
Film Thickness ◽  
Bulk Material ◽  
Substrate Surface ◽  
Cluster Formation ◽  
Interface Layer ◽  
Native Oxide ◽  
Initial Growth ◽  
Difference Spectra ◽  
Si Substrates

ABSTRACTThe growth of high quality amorphous hydrogenated semiconductor films was explored with different in situ spectroscopic methods. Nucleation of ArF laser-induced CVD of a-Ge:H on different substrates was investigated by real time ellipsometry, whereas the F2 laser (157nm) deposition of a-Si:H was monitored by FTIR transmission spectroscopy. The ellipsometric studies reveal a significant influence of the substrate surface on the nucleation stage, which in fact determines the electronic and mechanical properties of the bulk material. Coalescence of initial clusters occurs at a thickness of 16 Å for atomically smooth hydrogen-terminated c-Si substrates, whereas on native oxide covered c-Si substrates the bulk volume void fractions are not reached until 35 Å film thickness. For the first time we present a series of IR transmission spectra with monolayer resolution of the initial growth of a-Si:H. Hereby the film thickness was measured simultaneously using a quartz crystal microbalance with corresponding sensitivity. The results give evidence for cluster formation with a coalescence radius of about 20 Å. Difference spectra calculated for layers at different depths with definite thickness reveal that the hydrogen-rich interface layer stays at the substrate surface and does not move with the surface of the growing film. The decrease of the Urbach energy switching from native oxide to H-terminated substrates suggests a strong influence of the interface morphology on the bulk material quality.

Chemical Properties of A-Si:H Interface Layers on Oxide-Covered and Hydrogen-Terminated Silicon

1996 ◽  
Vol 420 ◽  
Author(s):  
Jürgen Knobloch ◽  
Peter Hess
Keyword(s):  
Film Growth ◽  
Substrate Surface ◽  
Chemical Properties ◽  
Deposition Process ◽  
Native Oxide ◽  
Difference Spectra ◽  
Initial Stage ◽  
Laser Cvd ◽  
Interface Layers

AbstractHigh quality a-Si:H films were deposited by pulsed VUV (157nm) laser CVD, allowing digital control of the deposition process. Nucleation and growth on native oxide-covered Si (100) and on H-terminated Si (111) surfaces were studied in situ by FTIR transmission spectroscopy with sub-monolayer sensitivity. The film thickness was monitored simultaneously using a quartz crystal microbalance (QCM) with comparable resolution. The in situ spectra reveal that the nature of the substrate surface significantly influences the hydrogen bonding configuration in the interface region. In both cases the assumed cluster growth during the initial stage is characterized by a band around 2100cm−1, which is assigned to SiHX (x = 1 – 3) surface modes. This band broadens until the clusters coalesce and band saturation occurs. At this time a second band starts to grow at 2000cm−1, which is attributed to bulk SiH bonds. Difference spectra calculated for layers at different depths with definite thickness and the deconvolution of the broad feature observed during the very first stage of film growth indicate the existence of a hydrogen-rich layer at the substrate surface whose composition and thickness depend on the properties of the substrate surface.

Study on the Growth of Crystalline Er2O3 Films on Si Substrates by RHEED Patterns

2011 ◽  
Vol 486 ◽  
pp. 163-166
Author(s):  
Yan Yan Zhu ◽  
Run Xu ◽  
Ze Bo Fang
Keyword(s):  
Film Growth ◽  
Interface Layer ◽  
High Energy ◽  
High Substrate Temperature ◽  
Initial Growth ◽  
High Energy Electron ◽  
Si Substrates ◽  
Good Crystallinity ◽  
Oxidation Effect

Er2O3 films with good crystallinity have been achieved on an oxidized Si (111) surface by molecule beam epitaxy. The initial growth of Er2O3 films epitaxially grown on Si surfaces is investigated by in situ reflection high energy electron diffraction. An interface layer was formed at the very beginning of the growth of Er2O3 film on Si, which is supposed to be attributed to the Er atom catalytic oxidation effect. The results obtained indicate that with the film growth process continued, oxygen deficient Er oxide captures oxygen from the interface layer which is formed inevitably at the initial growth of Er2O3 film and thus reduce and even remove the interface layer if the condition of O2 pressure is insufficient at a high substrate temperature such as 700°C in our case.

Formation Mechanism of Epitaxial CoSi2 Films on (001) Si Using Ti-Co Bimetallic Layer Source Materials

1992 ◽  
Vol 280 ◽  
Author(s):  
S. L. Hsia ◽  
T. Y. Tana ◽  
P. L. Smith ◽  
G. E. Mcguire
Keyword(s):  
Film Formation ◽  
Substrate Surface ◽  
Native Oxide ◽  
Formation Processes ◽  
Mechanism Of Formation ◽  
Si Substrate ◽  
Barrier Material ◽  
Si Substrates ◽  
Bimetallic Layer ◽  
Source Materials

ABSTRACTThe mechanism of formation of epitaxial CoSi2 film on (001) Si substrate, produced using sequentially deposited Ti-Co bimetallic layer source materials for which Ti was deposited onto the Si substrates first, has been studied by observing the Co silicide formation processes and structures in samples prepared by isochronal annealing and by isothermal annealing. The results demonstrated that, in leading to epitaxial CoSi2 film formation, Ti has played two roles. It has served as a barrier material to Co atoms and thus preventing Co2Si from forming. More importantly, it has allowed nucleation and growth of epitaxial-CoSi2 to dominate the Co silicide film formation process, apparently because it has served as a cleanser to remove native oxide from the Si substrate surface.

The Initial Epitaxy of Copper on (111) Gold Single Crystals

1975 ◽  
Vol 33 ◽  
pp. 98-99
Author(s):  
J. E. Macur
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Substrate Surface ◽  
Base Pressure ◽  
Initial Growth ◽  
Sensitive Technique ◽  
Free Environment

Two of the primary requirements needed for a successful study of epitaxy are a contamination free environment (UHV) and an extremely smooth, clean substrate surface. The deposition should be studied in situ by means of some surface sensitive technique (e.g. RHEED or LEED) and then in TEM and TED. Such a study has been conducted with Cu on (111) Au.Extremely smooth (111) single crystals of Au were evaporated on NaCl/mica in a UHV-RHEED system whose base pressure was 7 x 10-10 torr. After a 15 minute anneal at 625°C the films were cooled to room temperature. The initial growth of Cu on (111) Au at room temperature was studied is the following manner. Fractions of a monolayer of Cu were deposited (~1A per minute) onto the Au substrate and immediately examined in RHEED.

TEM Study of Coherently Tilted YBa2Cu3O7-δ Thin Films on (305) SrTiO3 Substrates

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3342-3344
Author(s):  
Y. Yang ◽  
J. Gao
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Growth Stage ◽  
Substrate Surface ◽  
Single Domain ◽  
Initial Growth ◽  
Ybco Films ◽  
Microstructural Study ◽  
Initial Growth Stage ◽  
Axis Parallel

Microstructural study has been carried out on the YBa2Cu3O 7-δ (YBCO) thin films grown on (305) SrTiO3 (STO) substrates. The results show that the YBCO films are coherently tilted with the c-axis parallel to the [001] direction of STO. Small antidomains are nucleated at the initial growth stage. When the film thickness increases, antidomains disappear leading to the formation of single domain thin films. Some particles are observed above the defective substrate surface, but the film with the favorable orientation suppresses their further growth.

In Situ Spectroscopic Ellipsometry Study of the Oxide Etching and Surface Damaging Processes on Silicon Under Hydrogen Plasma

1999 ◽  
Vol 591 ◽  
Author(s):  
I.M. Vargas ◽  
J.Y. Manso ◽  
J.R. Guzmán ◽  
B.R. Weiner ◽  
G. Morell
Keyword(s):  
Spectroscopic Ellipsometry ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Surface Damage ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Si Substrates ◽  
Oxide Etching

ABSTRACTWe employed in situ ellipsometry in the monitoring of surface damage to monocrystalline silicon (Si) substrates under hydrogen plasma conditions. These measurements were complemented with spectroscopic ellipsometry and Raman spectroscopy, in order to characterize the surface conditions. It was found that heating the Si substrate to 700°C in the presence of molecular hydrogen produces etching of the native oxide layer, which is typically 10 Å thick. When the already hot and bare silicon surface is submitted to hydrogen plasma, it deteriorates very fast, becoming rough and full of voids. Modeling of the spectroscopic ellipsometry data was used to obtain a quantitative physical picture of the surface damage, in terms of roughness layer t ickness and void fraction. The results indicate that by the time a thin film starts to grow on these silicon surfaces, like in the chemical vapor deposition of diamond, the roughness produced by the hydrogen plasma has already determined to a large extent the rough nature of the film to be grown.

Epitaxial Realignment of In-Situ Doped Polycrystalline Silicon for Advanced BiCMOS Technologies

1999 ◽  
Vol 587 ◽  
Author(s):  
K. Chang ◽  
S.G. Thomas ◽  
T-C. Lee ◽  
R.B. Gregory ◽  
D. O'meara ◽  
...  
Keyword(s):  
Polycrystalline Silicon ◽  
Chemical Vapor ◽  
Layer Growth ◽  
Native Oxide ◽  
Post Deposition Annealing ◽  
Si Substrates ◽  
Si Films ◽  
Post Deposition

AbstractIndustrial feasibility of an in-situ-doped (ISD) polycrystalline Si process using chemical vapor deposition for advanced BiCMOS technologies is presented. ISD As-doped amorphous and polycrystalline Si layers have been deposited on Si substrates at 610°C and 660°C, respectively, with the deposition rate varying from 120 to 128Å /minute. Samples are compared on the basis of having been subjected to a substrate preclean prior to deposition using an HF solution and an in-situ H2 bake. TEM micrographs reveal the presence of a thin (10-15 Å) native oxide at the deposited layer/substrate interface for samples not precleaned. This is confirmed for both the amorphous and polycrystalline Si depositions. However, for the 610°C-deposited samples given the substrate preclean, a polycrystalline structure with partial epitaxial layer growth is observed. Twins and stacking faults are found at the poly Si/single crystal Si interface, causing interfacial roughness. Post-deposition annealing of the Si films typically generates grain growth, but RBS-channeling characterization of the annealed Si provides evidence of some recrystallization, the extent of which is affected by the original growth condition. Analysis shows that the amorphous deposition at 610°C results in a mixture of epitaxial and polycrystalline Si. Epitaxial realignment of the polycrystalline Si film by post deposition annealing can result in significantly improved device performance.

Laser-Reflectance Interferometry Measurements of Diamond-Film Growth

MRS Bulletin ◽  
1995 ◽  
Vol 20 (5) ◽  
pp. 29-31 ◽  
Author(s):  
Christopher D. Zuiker ◽  
Dieter M. Gruen ◽  
Alan R. Krauss
Keyword(s):  
Film Thickness ◽  
Film Growth ◽  
Substrate Surface ◽  
Diamond Films ◽  
Thin Film Deposition ◽  
Film Deposition ◽  
Index Of Refraction ◽  
Ex Situ ◽  
Laser Reflectance

The remarkable properties of diamond, including its hardness, chemical inertness, high thermal conductivity, low coefficient of friction, optical transparency, and semiconducting properties, have led to considerable research in the area of diamond thin-film deposition. Diamond films have been characterized ex situ by a large number of diagnostic techniques including Raman spectroscopy, x-ray diffraction, SEM, and TEM. In situ diagnostics, which can provide information in real time as the film is growing, are less common.Laser-reflectance interferometry (LRI) has been used to monitor the growth of diamond films in situ. The technique involves measuring the intensity of a laser beam reflected from the substrate surface on which the film is growing. The reflected beam is the sum of beams reflected by the gas-diamond interface and the diamond-silicon interface. Oscillations in the reflectivity are observed as the film grows because of interference between the reflected beams. Each oscillation indicates an increase in film thickness of λ/2n, where λ is the laser wavelength and n is the index of refraction of the film. If the index of refraction of the film is known, the thickness and growth rate can be determined in situ. For LRI measurements with 632.8-nm-wavelength HeNe lasers, the index of refraction of diamond films has been found to be within 10% of the bulk diamond value of 2.4. Each oscillation therefore indicates an increase in film thickness of 0.13 μm.The reflectivity measured by LRI is also affected by scattering because of surface roughness.

Native Oxide and the Residual Stress of Thin Mo and Ta Films

1996 ◽  
Vol 441 ◽  
Author(s):  
L. J. Parfitt ◽  
Z. U. Rek ◽  
S. M. Yalisove ◽  
J. C. Bilello
Keyword(s):  
Residual Stress ◽  
Film Thickness ◽  
Compressive Stress ◽  
Advanced Characterization ◽  
Grazing Incidence ◽  
Deposition Process ◽  
Native Oxide ◽  
Native Oxide Layer ◽  
Si Substrates ◽  
Transmission Electron

AbstractResidual stress changed substantially between 2.5 and 80 nm film thickness in very thin Mo and Ta coatings sputtered onto Si substrates with native oxide. For both Mo and Ta, the thinnest films had a high compressive stress on the order of 2 to 3 GPa, and the stress relaxed, or became slightly tensile, with increasing film thickness. The coatings were examined using a variety of advanced characterization techniques including Auger Electron Spectroscopy (AES), Grazing Incidence X-ray Scattering (GIXS), and High Resolution Transmission Electron Microscopy (HRTEM). AES showed the presence of 0 and C contamination at the interface between the substrate and the film; these impurities originated from the adsorbed species and the native oxide on the surface of the wafers. GIXS analysis of the Mo films showed that the lattice of the thinnest layers was considerably expanded compared to the interplanar spacing of bulk, pure Mo. This expansion was caused by incorporation of impurities from the substrate into interstitial sites, which caused the very high compressive stress. HRTEM showed that the sputter deposition process did not alter the thickness of the native oxide layer, suggesting that the Mo and Ta films interacted with only the adsorbed impurities and the top one or two layers of the SiO2. Mo films deposited onto clean W layers were tensile, which supported the hypothesis that impurities caused the high compressive stresses in the films deposited onto SiO2. Grain growth and phase transformations contributed to the relaxation in stress observed in the thicker films.

Origins of Residual Stress in Mo and Ta Films: the Role of Impurities, Microstructural Evolution, and Phase Transformations

1996 ◽  
Vol 436 ◽  
Author(s):  
L. J. Parfitt ◽  
O. P. Karpenko ◽  
Z. U. Rek ◽  
S. M. Yalisove ◽  
J. C. Bilello
Keyword(s):  
Residual Stress ◽  
Film Thickness ◽  
Phase Transformations ◽  
Compressive Stress ◽  
Native Oxide ◽  
Si Substrates ◽  
Stress Behavior ◽  
Sputter Deposited ◽  
Substrate Surfaces ◽  
20 Nm

AbstractBoth the sign and magnitude of residual stress can vary with the thickness of sputter deposited films. The origins of this behavior are not well understood. In this work, we consider the correlation between the residual stress behavior and the depth dependence of impurities in thin (2.5 nm - 150 nm) sputtered Mo and Ta films. We also consider the effects of phase transformations and microstructural changes on the stress behavior. Films were deposited onto Si substrates with native oxide. The residual stress observed in the Mo films varied from highly compressive at 2.5 nm film thickness to ∼ 0 ˜ 10 nm thickness. Ta films also exhibited a high compressive stress, which relaxed from highly compressive to tensile between 10 nm and 50 nm film thickness. Impurities in the films may originate from the sputtering targets, the background gases, and the substrate surfaces. Auger Electron Spectroscopy (AES) results showed the presence of O and C contamination near the film/Si interface; these impurities contributed to the compressive stresses in the thinner films. As anticipated, both Mo and Ta films exhibited grain growth as a function of film thickness, which may have contributed to the relaxation in the compressive stress. The Mo films were entirely bcc. The Ta films showed a transformation from the amorphous phase to the β crystalline phase between 2.5 nm and 20 nm film thickness, which contributed to the relaxation in stress observed in that thickness regime.

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