In-Situ Rheed Observation of Mocvd-Gan Film Growth

2001 ◽  
Vol 693 ◽  
Author(s):  
Masatomo Sumiya ◽  
Noritaka Ogusu ◽  
Kouhei Osada ◽  
Shunro Fuke
Keyword(s):  
Buffer Layer ◽  
Film Growth ◽  
Deposition Process ◽  
Film Deposition ◽  
Total Flow ◽  
Total Flow Rate ◽  
Gan Film ◽  
Lattice Mismatched Substrate

AbstractWe developed the MOCVD apparatus equipped with RHEED system, which enable us to observe in-situ and real time RHEED for GaN film growth in ~100mTorr of pressure. We attempted to grow GaN film with this MOCVD chamber in 100mTorr. The in-situ RHEED was subsequently observed along the film deposition process in order to understand both the role of buffer layer and the mechanism of GaN film growth by MOCVD on highly lattice-mismatched substrate like sapphire. The results indicate that oxygen removed from the sapphire surface was observed during its cleaning in H2 flow at 1100°C. The dependence of re-crystallization and evaporation of the buffer layer on the annealing ambient was also detected. Although the nitrogen was slightly deficient, HT-GaN film with smooth surface was obtained in 100mTorr by adding H2 gas and reducing total flow rate. In preliminary deposition, the RHEED oscillation-like was observed in MOCVD-GaN growth. Thus, our developing deposition system has a potential to understand the growth mechanism with atomic level.

scholarly journals Controlling the flux of reactive species: a case study on thin film deposition in an aniline/argon plasma

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
D. Sciacqua ◽  
C. Pattyn ◽  
A. Jagodar ◽  
E. von Wahl ◽  
T. Lecas ◽  
...  
Keyword(s):  
Thin Films ◽  
Film Growth ◽  
Argon Plasma ◽  
Thin Film Deposition ◽  
Deposition Process ◽  
Film Deposition ◽  
Capacitively Coupled ◽  
Low Temperature Plasmas ◽  
Free Films

Abstract The plasma based synthesis of thin films is frequently used to deposit ultra-thin and pinhole-free films on a wide class of different substrates. However, the synthesis of thin films by means of low temperature plasmas is rather complex due to the great number of different species (neutrals, radicals, ions) that are potentially involved in the deposition process. This contribution deals with polymerization processes in a capacitively coupled discharge operated in a mixture of argon and aniline where the latter is a monomer, which is used for the production of plasma-polymerized polyaniline, a material belonging to the class of conductive polymers. This work will present a particular experimental approach that allows to (partially) distinguish the contribution of different species to the film growth and thus to control to a certain extent the properties of the resulting material. The control of the species flux emerging from the plasma and contributing to the film growth also sheds new light on the deposition process, in particular with respect to the role of the ion component. The analysis of the produced films has been performed by means of Fourier Transform Infrared spectroscopy (FTIR) and Near Edge X-ray Absorption Fine Structure spectroscopy (NEXAFS).

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.

Retarded Growth of Sputtered HfO2 Films on Germanium

2004 ◽  
Vol 811 ◽  
Author(s):  
Koji Kita ◽  
Masashi Sasagawa ◽  
Masahiro Toyama ◽  
Kentaro Kyuno ◽  
Akira Toriumi
Keyword(s):  
Film Growth ◽  
Early Stage ◽  
Gate Oxide ◽  
Interface Layer ◽  
Film Deposition ◽  
Si Substrate ◽  
Equivalent Thickness ◽  
Ternary Compounds ◽  
Si Substrates

ABSTRACTHfO2 films were deposited by reactive sputtering on Ge and Si substrates simultaneously, and we found not only the interface layer but the HfO2 film was thinner on Ge substrate compared with that on Si substrate. A metallic Hf layer has a crucial role for the thickness differences of both interface layer and HfO2 film, since those thickness differences were observed only when an ultrathin metallic Hf layer was predeposited before HfO2 film deposition. The role of metallic Hf is understandable by assuming a formation of volatile Hf-Ge-O ternary compounds at the early stage of film growth. These results show an advantage of HfO2/Ge over HfO2/Si systems from the viewpoint of further scaling of electrical equivalent thickness of the gate oxide films.

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.

High Throughput Optimization of Y-Type Magnetoplumbite Epitaxial thin Film Growth by Combinatorial Pulsed Laser Deposition Technique

2001 ◽  
Vol 700 ◽  
Author(s):  
I. Ohkubo ◽  
Y. Matsumoto ◽  
M. Ohtani ◽  
T. Hasegawa ◽  
K. Ueno ◽  
...  
Keyword(s):  
Pulsed Laser Deposition ◽  
Buffer Layer ◽  
Film Growth ◽  
Pulsed Laser ◽  
Deposition Process ◽  
Thin Film Growth ◽  
Laser Deposition ◽  
Throughput Optimization ◽  
Tem Analysis ◽  
First Time

AbstractThin films of Y-type magnetoplumbite (Ba2Co2Fe12O22: Co2Y) with such a huge unit cell length as 43.5 Å has been successfully fabricated for the first time with the aid of combinatorial optimization of pulsed laser deposition process. Planning a thickness gradient CoO buffer layer on MgAl2O4(111) substrate was very effective for prevent the phase separation of Co deficient impurity (BaFe2O4) to reside in the formation of desired Co2Y phase.From the TEM analysis, the CoO buffer layer of optimum thickness was incorporated into the Co2Y film to make theinterface with the make an atomically sharp.

Threshold Value of Particle Concentration in EPD: Experimental Evidence with TiO2 Organic Suspensions

2009 ◽  
Vol 412 ◽  
pp. 51-56 ◽  
Author(s):  
Simona Radice ◽  
Stefano Mischler ◽  
Johann Michler
Keyword(s):  
Particle Concentration ◽  
Deposition Time ◽  
Threshold Value ◽  
Deposition Process ◽  
Suspension Systems ◽  
Limit Value ◽  
Coating Formation ◽  
Concentration Threshold

This study was triggered by our experience on electrophoretic deposition (EPD) with different suspension systems showing evidence of a particle concentration threshold, below which no deposit was formed. In this study, the role of particle concentration in the mechanism of EPD was investigated with a model system, consisting of isopropanol suspensions with TiO2 nanosized particles (d50 = 130 nm). The investigated concentration range was 0.01 - 0.4 vol% TiO2. Constant voltage EPD tests with variable particle concentration were performed for 1 min under different applied voltages (25 - 300 V corresponding to 62.5 - 750 V/cm). A longer deposition time (30 min) was tested for a lower concentration value (0.003 vol% TiO2). The deposition process was evaluated in situ by means of the current measured during EPD. The deposits obtained were characterized by weight and profile measurements and scanning electron microscope (SEM). The results confirmed the finding of a lower limit value of particle concentration, determining a threshold in the formation of an EPD coating. Above this threshold, proportionality between deposited mass and particle concentration was observed, in agreement with the equation of Hamaker. Below this threshold, the proportionality was lost with evidence of a lack of coating formation. A possible interpretation for this experimental finding was provided.

In-situ Multilayer Film Growth Characterization by Brewster Angle Reflectance Differential Spectroscopy

1993 ◽  
Vol 324 ◽  
Author(s):  
N. Dietz ◽  
D.J. Stephens ◽  
G. Lucovsky ◽  
K.J. Bachmann
Keyword(s):  
Optical Constants ◽  
Multilayer Film ◽  
Film Growth ◽  
Polarized Light ◽  
Layer Growth ◽  
Brewster Angle ◽  
Film Deposition ◽  
In Situ Monitoring ◽  
Differential Spectroscopy

AbstractBrewster Angle Reflectance Differential Spectroscopy (BARDS) has been proposed as an optical method for real-time characterization of the growth of thin films. BARDS is based on changes in the reflectivity, Rp, of parallel (p)-polarized light incident at, or near, the Brewster angle of the substrate material. Changes in R are sufficiently large to monitor layer growth, and to determine the thickness and the optical constants of the deposited film. In this paper we extend the method to multilayer film deposition. The derivative properties of R are correlated with differences in the optical constants of the two materials, and with the sharpness of their interface. We present spectra for SiO2/Si3N4/SiO2/Si, demonstrating some of these aspects of this new and effective approach to in-situ monitoring.

Thick cubic GaN film growth using ultra-thin low-temperature buffer layer by RF–MBE

2005 ◽  
Vol 278 (1-4) ◽  
pp. 411-414 ◽  
Author(s):  
Ryuhei Kimura ◽  
Takeaki Suzuki ◽  
Masamichi Ouchi ◽  
Kouichi Ishida ◽  
Kiyoshi Takahashi
Keyword(s):  
Low Temperature ◽  
Buffer Layer ◽  
Film Growth ◽  
Cubic Gan ◽  
Gan Film

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.

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