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.

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.

In situ transient study of polymer film growth via simultaneous correlation of charge, mass, and ellipsometric measurements

2008 ◽  
Vol 80 (11) ◽  
pp. 2439-2449 ◽  
Author(s):  
Vojtech Svoboda ◽  
Bor Yann Liaw
Keyword(s):  
Polymer Film ◽  
Quartz Crystal ◽  
Spatial Information ◽  
Film Growth ◽  
Deposition Process ◽  
Imaging Ellipsometry ◽  
Adsorption Reduction ◽  
Temporal And Spatial ◽  
Transient Study

Using three synchronized, in situ, nonintrusive, real-time characterization techniques to conduct transient observations, we revealed mechanistic details of a polymer film growth. A thin methylene green (MG) polymer coating (of the order of 35 nm) was used as a model system in this electrochemical microgravimetric imaging ellipsometry (EmIE) investigation. The direct correlation of changes in mass (via quartz crystal microbalance, QCM), ellipsometric angles (via imaging ellipsometry) with electrochemical conditions (in cyclic voltammetry, CV) provides discrete temporal and spatial information to help us decipher the underlying steps, from which we were able to separate adsorption, reduction, oxidation, desorption, and polymerization regimes involved in the deposition process. The evidence revealed in this study could have broad impact on the general understanding regarding how a film is deposited onto a metal surface.

In-Situ Observation of Chemical Vapor Deposition of Thin Sige Films by Optical Reflection Interferometry

1994 ◽  
Vol 375 ◽  
Author(s):  
G. Ritter ◽  
B. Tillack ◽  
M. Weidner ◽  
F. G. Böbel ◽  
B. Hertel
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Ex Situ ◽  
In Situ Observation ◽  
Optical Reflection ◽  
Initial Stage

AbstractChemical Vapor Deposition of Si1-x Gex – films on Si (100) and of polycrystalline Si1-x Gex, layers on SiO2 – coated substrates have been performed at a pressure of 200 Pa in the temperature range of 500°C – 800°C, correspondingly. To observe the growth process and to characterize the growing thin films at deposition conditions an optical reflection interferometer (PYRITIERS) has been used. Comparing the data obtained at growth temperature with ex- situ measurements by spectroscopic ellipsometry the temperature dependence of optical constants of SiGe films have been evaluated. The reflectivity measurements during the deposition process allow to study the quality of the heteroepitaxial film, even in the initial stage of epitaxial growth.

Microstructural Identification of SiNx Films by Real-Time Ellipsometry

1997 ◽  
Vol 472 ◽  
Author(s):  
G. Soto ◽  
E. C. Samano ◽  
R. Machorro ◽  
M. Avalos ◽  
L. Cota
Keyword(s):  
Real Time ◽  
Film Growth ◽  
Incidence Angle ◽  
Polarization State ◽  
Sample Surface ◽  
Deposition Process ◽  
Slight Variation ◽  
Si Substrates ◽  
Amorphous Si

ABSTRACTReal-time ellipsometry has shown to be a powerful tool to analyze thin films during processing. It is non-disturbing and its sensitivity lies in the submonolayer range. In fact, a slight variation in the film microstructure might result in a significant change of the polarization state of the reflected beam from the sample surface. SiNx layers have been grown on glass, quartz, KC1 and Si substrates by laser ablating a Si3N4 sintered target in vacuum and N2 environment. The film growth was monitored by real time ellipsometry at a fixed wavelength, and a fixed incidence angle. Once the deposition process is completed, the refractive index was obtained by perfoming in situ spectroellipsometric measurements in the 1.5 to 5 eV photon-energy range. The best curve fitting of the experimental data is used to find the film composition: a mixture of Si3N4, polycrystalline Si, and amorphous Si. The films composition and micro structure inferred from ellipsometric data are compared to those obtained by in-situ surface techniques and TEM, respectively.

Excimer Laser Induced Deposition of Tungsten from W(CO)6 and WF6

1989 ◽  
Vol 158 ◽  
Author(s):  
Berthold Rager ◽  
Friedrich Bachmann
Keyword(s):  
Deposition Time ◽  
Deposition Process ◽  
Layer Growth ◽  
X Ray Diffraction ◽  
Reflectivity Measurement ◽  
Model Calculations ◽  
Deposition Parameters ◽  
Initial Stage ◽  
Deposited Films

ABSTRACTArF laser induced deposition of W from W(CO)6 and WF6 on Si/SiO2 surfaces was investigated. With an in-situ reflectivity measurement the growth of the layer could be monitored during the deposition process. We find that the initial stage of layer growth as well as the reflectivity as a function of deposition time depends on the laser fluence and on other deposition parameters. Model calculations, using the optical constants of deposited films, determined by ellipsometry, have been performed to compare the measured reflectivity curves with the calculated curves. The deposited layers have been analyzed by XPS, AES, X-ray Diffraction and Raman Spectroscopy. Additionally, experiments of direct pattern transfer deposition (via contact mask) with W(CO)6 show the presence of an involved surface process, which by Fresnel diffraction caused structures smaller than 0.5μm.

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.

Studies of SiH2Ci2/H2 Gas Phase Chemistry for Selective Thin Film Growth of Crystalline Silicon, c-Si, Using Remote Plasma Enhanced Chemical Vapor Deposition

1991 ◽  
Vol 220 ◽  
Author(s):  
J. A. Theil ◽  
G. Lucovsky ◽  
S. V. Hattangady ◽  
G. G. Fountain ◽  
R. J. Markunas
Keyword(s):  
Gas Phase ◽  
Film Growth ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Film Deposition ◽  
Selective Deposition ◽  
Gas Phase Chemistry ◽  
Phase Chemistry

ABSTRACTConventional high temperature, >800°C, CVD processes, utilizing SiH2Ci2 promote selective deposition of c-Si onto c-Si, but not on SiO2 surfaces. We show that low temperature, 300°C remote PECVD, with rf-excited He plasmas, and SiH2Ci2 and H2 injected downstream, also selectively deposits c-Si on c-Si and not SiO2 surfaces. This preliminary study employs in-situ mass spectrometry, MS, to determine the species responsible for selective deposition process reaction pathways. These MS studies suggest that species responsible for film deposition are Si-containing fragments of the SiH2Ci2 molecule, e.g., SiH2Ci, SiCi2H, etc., while the species responsible for inhibiting deposition on the SiO2 surfaces are by-products of the break-up of the SiH2Ci2 molecule in the gas phase, e.g., H-atoms, HCI and H2Ci+ ions.

In Situ Electron Spectroscopic Identification of Carbon Species Deposited by Laser Ablation

1996 ◽  
Vol 436 ◽  
Author(s):  
E. C. Samano ◽  
Gerardo Soto ◽  
Arturo Gamietea ◽  
Leonel Cota
Keyword(s):  
Substrate Surface ◽  
Pyrolytic Graphite ◽  
Deposition Process ◽  
Carbon Films ◽  
Spectroscopic Techniques ◽  
Carbon Species ◽  
Thin Carbon ◽  
Spectroscopic Identification ◽  
Relationship Of

AbstractThin carbon films were grown on Si (111) substrates by ablating a graphite target utilizing an excimer pulsed laser in a UHV Riber © LDM-32 system. Two kinds of films were produced, a highly oriented pyrolytic graphite (HOPG) type and a diamond-like carbon (DLC) type. A relationship of the films microstructure with laser power density and substrate conditions was observed. The HOPG films were homogeneous but the DLC films were heterogeneous, as shown by micrographs. The thin films are monitored and analyzed in situ during the first stages of the deposition process. The monitoring was done by RHEED and the characterization by several surface spectroscopic techniques, AES, XPS and EELS. The formation of a SiC interface was observed for both films due to the reaction of the first carbon species with the substrate surface.

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