Atomic-Scale Analysis of Plasma-Enhanced Chemical Vapor Deposition from SiH4/2 Plasmas on Si Substrates

1998 ◽  
Vol 507 ◽  
Author(s):  
Shyam Ramalingam ◽  
Dimitrios Maroudas ◽  
Eray S. Aydil
Keyword(s):  
Gas Phase ◽  
Surface Reaction ◽  
Film Growth ◽  
Chemical Vapor ◽  
Atomic Scale ◽  
Scale Analysis ◽  
Si Substrates ◽  
Stages Of Growth ◽  
Key Factor ◽  
Reaction Processes

ABSTRACTWe present a systematic atomic-scale analysis of the interactions of SiH3radicals originating in silane containing discharges with Si(001)-(2×1) and H-terminated Si(001)-(2×1) surfaces. Through simulations, we show that the hydrogen coverage of the surface is the key factor that controls both the surface reaction mechanism and the reaction probability. The SiH3radical reacts readily with the pristine Si(001)-(2×1) surface during the initial stages of growth while its reactivity with the corresponding H-terminated surface is considerably lower. Deposition of a-Si:H from SiH3 radicals has also been simulated by repeatedly impinging SiH3 radicals onto Si(001)-(2×1) surfaces maintained at 500 °C. During deposition under these conditions, the dominant mechanism of hydrogen removal from the surface is through abstraction by SiH3 radicals, which subsequently return to the gas phase as silane. The important reaction processes that take place during film growth have been identified and their energetics has been analyzed.

Kinetics of Diamond-Like Film Growth Using Filament-Assisted Chemical Vapor Deposition

1994 ◽  
Vol 363 ◽  
Author(s):  
G. Gorsuch ◽  
Y. Jin ◽  
N. K. Ingle ◽  
T. J. Mountziarisi ◽  
W.-Y. Yu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Kinetic Model ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Film Growth ◽  
Transport Model ◽  
Surface Reactions ◽  
Chemical Vapor ◽  
Surface Kinetics ◽  
Si Substrates

AbstractA detailed kinetic model of diamond-like film growth from methane diluted in hydrogen using low-pressure, filament-assisted chemical vapor deposition (FACVD) has been developed. The model includes both gas-phase and surface reactions. The surface kinetics include adsorption of CH3· and H·, abstraction reactions by gas-phase radicals, desorption, and two pathways for diamond (sp3) and graphitic carbon (sp2) growth. It is postulated that adsorbed CH2· species are the major film precursors. The proposed kinetic model was incorporated into a transport model describing flow, heat and mass transfer in stagnation flow FACVD reactors. Diamond-like films were deposited on preseeded Si substrates in such a reactor at a pressure of 26 Torr, inlet gas composition ranging from 0.5% to 1.5% methane in hydrogen and substrate temperatures ranging from 600 to 950°C. The best films were obtained at low methane concentrations and substrate temperature of 700°C. The films were characterized using Scanning Electron Microscopy (SEM) and Raman spectroscopy. Observations from our experiments and growth rate data from similar experiments reported in the literature [1] were used to estimate unknown kinetic parameters of surface reactions. The proposed model predicts observed film growth rates, compositions and stable species distributions in the gas phase. It is the first complete model of FACVD that includes gas-phase and surface kinetics coupled with transport phenomena.

A Study on CVD TaN as a Diffusion Barrier for Cu Interconnects

2000 ◽  
Vol 612 ◽  
Author(s):  
Se-Joon Im ◽  
Soo-Hyun Kim ◽  
Ki-Chul Park ◽  
Sung-Lae Cho ◽  
Ki-Bum Kim
Keyword(s):  
Activation Energy ◽  
Gas Phase ◽  
Diffusion Barrier ◽  
Surface Reaction ◽  
Film Growth ◽  
Ion Beam ◽  
Barrier Properties ◽  
Tantalum Nitride ◽  
X Ray Diffraction ◽  
X Ray

AbstractTantalum nitride (TaN) films were deposited using pentakis-diethylamido-tantalum [PDEAT, Ta(N(C2H5)2)5] as a precursor. During film growth, N- and Ar-ion beams with an energy of 120 eV were supplied in order to improve the film quality. In case of thermallydecomposed films, the deposition rate is controlled by the surface reaction up to about 350 °C with an activation energy of about 1.07 eV. The activation energy of the surface reaction controlled regime is decreased to 0.26 eV when the Ar-beam is applied. However, in case of Nbeam bombarded films, the deposition is controlled by the precursor diffusion in gas phase at the whole temperature range. By using Ar-beam, the resistivity of the film is drastically reduced from approximately 10000 µω-cm to 600 µω-cm and the density of the film is increased from 5.85 g/cm3 to 8.26 g/cm3, as compared with thermally-decomposed film. The use of N-beam also considerably lowers the resistivity of films (∼ 800 µω-cm) and increases the density of the films (7.5 g/cm3). Finally, the diffusion barrier properties of 50-nm-thick TaN films for Cu were investigated aftre annealing by X-ray diffraction analysis. The films deposited using N- and Arbeam showed the Cu3Si formation after annealing at 650 °C for 1 hour, while thermallydecomposed films showed Cu3Si peaks firstly after annealing at 600 °C. It is considered that the improvements of the diffusion barrier performance of the films deposited using N- and Ar-ion beam are the consequence of the film densification resulting from the ion bombardment during film growth.

Sub-Surface Equilibration of Hydrogen with the a-Si:H Network Under Film Growth Conditions

1993 ◽  
Vol 297 ◽  
Author(s):  
ILSIN An ◽  
Y.M. Li ◽  
C.R. Wronski ◽  
R. W. Collins
Keyword(s):  
Hydrogen Diffusion ◽  
Film Growth ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
Emission Rates ◽  
Near Surface ◽  
Kinetic Information ◽  
Reaction Processes ◽  
Surface Conversion

In this study we characterize hydrogen diffusion and reaction processes in the near-surface (top 200 Å) of a-Si:H that lead to network equilibration under standard conditions of plasma-enhanced chemical vapor deposition (PECVD). Real time spectroscopic ellipsometry (SE) is used to provide continuous kinetic information on the near-surface conversion of Si-Si to Si-H bonds during exposure of in situ-prepared films at 250°C to filament-generated atomic H. We have found that for optimum PECVD a-Si:H, the formation of additional Si-H bonds is limited by the capture of H at trapping sites, and the rapid diffusion process (D>10-14 cm2/s) by which H reaches the site is not detected optically. Deep trapping occurs at a rate of ∼10 3 s-1 under our filament conditions, estimated to generate ∼1020 cm-3 mobile H in the near-surface of the film. Finally, more than 1021 cm-3 additional H atoms are trapped with emission rates <2×10-7 s-1, suggesting trap depths >2.0 eV. Shallower traps are also detected at lower concentration.

The interaction of chemical kinetics and diffusion in the dynamics of chemical vapor infiltration

1989 ◽  
Vol 4 (6) ◽  
pp. 1515-1524 ◽  
Author(s):  
Stanley Middleman
Keyword(s):  
Gas Phase ◽  
Film Growth ◽  
Classical Model ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Reactor Model ◽  
Cylindrical Pore ◽  
Complex Chemistry ◽  
And Diffusion ◽  
Vapor Infiltration

The classical model of Chemical Vapor Infiltration (CVI) treats diffusion and surface reaction in a representative cylindrical pore. Two significant modifications to that approach are presented herein. One accounts for more complex chemistry by allowing for both gas-phase and surface reactions which lead to film growth. The other couples the pore model to a reactor model for the region external to the porous preform. The results demonstrate that it is possible to select chemical schemes that yield densification from the interior to the exterior of the preform, thus avoiding premature trapping of interior voids.

Deposition of Ceramic Films by A Novel Pulsed-Gas Mocvd Technique

1992 ◽  
Vol 271 ◽  
Author(s):  
Kenneth A. Aitchison ◽  
James D. Barrie ◽  
Joseph Ciofalo
Keyword(s):  
Gas Phase ◽  
Film Growth ◽  
Flow Reactor ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Film Deposition ◽  
Organic Chemical ◽  
Oxide Systems ◽  
Metal Organic ◽  
Mocvd Technique

ABSTRACTMetal-Organic Chemical Vapor Deposition (MOCVD) is a versatile technique for the deposition of thin films of metals, semiconductors and ceramics. Commonly used hot wall flow-reactor designs suffer from a number of limitations. Chemical processes occurring in these reactors typically include a combination of homogeneous (gas-phase) and heterogeneous (gas-surface) reactions. These complex conditions are difficult to model and are poorly understood. In addition, flow reactors use large quantities of expensive precursor materials and are not well suited to the formation of abrupt interfaces. We report here a novel MOCVD technique which addresses these problems and enables a more thorough mechanistic understanding of the heterogeneous decomposition pathways of metal-organic compounds. This technique, the low-pressure pulsed gas method, has been demonstrated to provide high deposition rates with excellent control over film thickness. The deposition conditions effectively eliminate homogeneous processes allowing surface-mediated reactions to dominate. This decoupling of gas-phase chemistry from film deposition allows a better understanding of reaction mechanisms and provides better control over film growth. Both single metal oxides and binary oxide systems have been investigated on a variety of substrate materials. Effects of precursor chemistry, substrate surface, temperature and pressure on film composition and morphology will be discussed.

Numerical Investigation of Pulsed Chemical Vapor Deposition of Aluminum Nitride to Reduce Particle Formation

2011 ◽  
Author(s):  
Derek Endres ◽  
Sandip Mazumder
Keyword(s):  
Gas Phase ◽  
Direct Contact ◽  
Gas Flow ◽  
Film Growth ◽  
Chemical Vapor ◽  
Particle Formation ◽  
Group V ◽  
Flow Rates ◽  
Group Iii ◽  
Reactor Pressure

Particles of aluminum nitride (AlN) have been observed to form during epitaxial growth of AlN films by metal organic chemical vapor deposition (MOCVD). Particle formation is undesirable because particles do not contribute to the film growth, and are detrimental to the hydraulic system of the reactor. It is believed that particle formation is triggered by adducts that are formed when the group-III precursor, namely tri-methyl-aluminum (TMAl), and the group-V precursor, namely ammonia (NH3), come in direct contact in the gas-phase. Thus, one way to eliminate particle formation is to prevent the group-III and the group-V precursors from coming in direct contact at all in the gas-phase. In this article, pulsing of TMAl and NH3 is numerically investigated as a means to reduce AlN particle formation. The investigations are conducted using computational fluid dynamics (CFD) analysis with the inclusion of detailed chemical reaction mechanisms both in the gas-phase and at the surface. The CFD code is first validated for steady-state (non-pulsed) MOCVD of AlN against published data. Subsequently, it is exercised for pulsed MOCVD with various pulse widths, precursor gas flow rates, wafer temperature, and reactor pressure. It is found that in order to significantly reduce particle formation, the group-III and group-V precursors need to be separated by a carrier gas pulse, and the carrier gas pulse should be at least 5–6 times as long as the precursor gas pulses. The studies also reveal that with the same time-averaged precursor gas flow rates as steady injection (non-pulsed) conditions, pulsed MOCVD can result in higher film growth rates because the precursors are incorporated into the film, rather than being wasted as particles. The improvement in growth rate was noted for both horizontal and vertical reactors, and was found to be most pronounced for intermediate wafer temperature and intermediate reactor pressure.

scholarly journals Study on the Microstructure and Electrical Properties of Boron and Sulfur Codoped Diamond Films Deposited Using Chemical Vapor Deposition

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Zhang Jing ◽  
Li Rongbin ◽  
Wang Xianghu ◽  
Wei Xicheng
Keyword(s):  
Grain Boundaries ◽  
Measurement Techniques ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
Si Substrates ◽  
Average Size

The atomic-scale microstructure and electron emission properties of boron and sulfur (denoted as B-S) codoped diamond films grown on high-temperature and high-pressure (HTHP) diamond and Si substrates were investigated using atom force microscopy (AFM), scanning tunneling microscopy (STM), secondary ion mass spectroscopy (SIMS), and current imaging tunneling spectroscopy (CITS) measurement techniques. The films grown on Si consisted of large grains with secondary nucleation, whereas those on HTHP diamond are composed of well-developed polycrystalline facets with an average size of 10–50 nm. SIMS analyses confirmed that sulfur was successfully introduced into diamond films, and a small amount of boron facilitated sulfur incorporation into diamond. Large tunneling currents were observed at some grain boundaries, and the emission character was better at the grain boundaries than that at the center of the crystal. The films grown on HTHP diamond substrates were much more perfect with higher quality than the films deposited on Si substrates. The localI-Vcharacteristics for films deposited on Si or HTHP diamond substrates indicate n-type conduction.

Low Temperature Chemical Vapor Deposition of 3C-SiC on Si Substrates

2005 ◽  
Vol 483-485 ◽  
pp. 201-204 ◽  
Author(s):  
Christian Förster ◽  
Volker Cimalla ◽  
Oliver Ambacher ◽  
Jörg Pezoldt
Keyword(s):  
Gas Phase ◽  
Vapor Deposition ◽  
Growth Process ◽  
Chemical Vapor ◽  
High Energy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force

In the present work an UHVCVD method was developed which allows the epitaxial growth of 3C-SiC on Si substrates at temperatures below 1000°C. The developed method enable the growth of low stress or nearly stress free single crystalline 3C-SiC layers on Si. The influence of hydrogen on the growth process are be discussed. The structural properties of the 3C-SiC(100) layers were studied with reflection high-energy diffraction, atomic force microscopy, X-ray diffraction and the layer thickness were measured by reflectometry as well as visible ellipsometry. The tensile strain reduction at optimized growth temperature, Si/C ratio in the gas phase and deposition rate are demonstrated by the observation of freestanding SiC cantilevers.

Growth kinetics of chemically vapor deposited SiO2 films from silane oxidation

1998 ◽  
Vol 13 (8) ◽  
pp. 2308-2314 ◽  
Author(s):  
Fernando Ojeda ◽  
Alejandro Castro-García ◽  
Cristina Gómez-Aleixandre ◽  
José María Albella
Keyword(s):  
Gas Phase ◽  
Deposition Rate ◽  
Growth Kinetics ◽  
Film Growth ◽  
Chemical Vapor ◽  
Intermediate Species ◽  
Pressure Oxygen ◽  
Pressure Chemical ◽  
Different Temperatures ◽  
Kinetics Of

The growth kinetics of SiO2 thin films obtained by low-pressure chemical vapor deposition (CVD) from SiH4/O2/N2 gas mixtures has been determined at different temperatures and flow rates. The results show that the film growth is originated by some intermediate species (e.g., SiOxHy) produced in the gas phase. At low temperatures the deposition rate is limited by some homogeneous reaction with an apparent activation energy of 1.42 eV. Furthermore, the observation of critical limits when total pressure, oxygen/silane flow ratio, and temperature are decreased gives support to a branching-chain mechanism of deposition. Finally, we have observed that the deposition rate shows a hysteresis behavior when varying the temperature within the 300–400 °C range, which has been attributed to the inhibition of silane oxidation by the Si–OH surface groups of the films grown on the reactor walls.

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