Electronic Excitation-Induced Surface Chemistry and Electron-Beam-Assisted Chemical Vapor Deposition

1989 ◽  
Vol 158 ◽  
Author(s):  
F. Bozso ◽  
Ph. Avouris
Keyword(s):  
Electron Beam ◽  
Film Growth ◽  
Molecular Layer ◽  
Chemical Vapor ◽  
Electronic Excitations ◽  
Precise Control ◽  
Selective Area ◽  
Low Energy Electron ◽  
Nitride Oxide ◽  
Molecular Layers

ABSTRACTSelective area deposition of thin films and surface structures with precise control over their composition is possible in UHV by using low energy electron beams to induce electronic excitations in adsorbed molecular layers. Upon electron impact, adsorbed/co-adsorbed molecules decompose into reactive species, resulting in film growth. The composition of the film reflects that of the adsorbed molecular layer, which at cryogenic temperatures can sensitively be controlled by the partial pressure of the reactant gases. We present results of detailed studies of adsorption, thermal and electron-beam-induced dissociation of disilane and ammonia on silicon. We show that by proper choice of temperature, gas phase composition and electron beam, amorphous silicon, silicon nitride, oxide, silicon oxinitride films can be grown with nearly monolayer thickness resolution.

Synthesis of Microcrystalline Silicon Films by Low Energy Electron-Beam-Induced Deposition at Cryogenic Temperature

2004 ◽  
Vol 832 ◽  
Author(s):  
Tetsuya Sato ◽  
Kiyokazu Nakagawa ◽  
Yutaka Aoki ◽  
Shouji Sato
Keyword(s):  
Electron Beam ◽  
Cryogenic Temperature ◽  
Chemical Vapor ◽  
Low Energy ◽  
Energy Electron ◽  
X Ray Diffraction ◽  
Microcrystalline Silicon ◽  
Raman Scattering Spectroscopy ◽  
Semiconductor Thin Films ◽  
Low Energy Electron

ABSTRACTWe have proposed an advanced method for formation of semiconductor thin films at substrates temperatures below 100K. We have synthesized amorphous silicon (a-Si:H) and microcrystalline silicon (μc-Si:H) films using low-energy electron-beam-induced-chemical vapor deposition (EBICVD) onto cooled substrates which adsorb source gases (SiH4 or Si2H6) at cryogenic temperature. The temperature dependence on growth rate of the films, hydrogen content and optical constants were investigated. The μc-Si:H could be formed at 40–45 K on SiO2 using He-discharged-EBICVD with SiH4. The crystallinity of silicon was evaluated by Raman scattering spectroscopy and X-ray diffraction.

Chemical Vapor Deposition of Ti-Si-N Films with Alternating Source Supply

1999 ◽  
Vol 564 ◽  
Author(s):  
Jae-Sik Min ◽  
Hyung-Sang Park ◽  
Wonyong Koh ◽  
Sang-Won Kang
Keyword(s):  
Atomic Layer Deposition ◽  
Film Growth ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Precise Control ◽  
Silicon Nitride Films ◽  
Layer Deposition ◽  
Si Content ◽  
Titanium Silicon Nitride ◽  
Titanium Silicon

AbstractTitanium-silicon-nitride films were grown by atomic layer deposition using an alternating supply of tetrakis(dimethylamido)titanium (TDMAT), silane. and ammonia, at substrate temperature of 180°C. The supply of a reactant was followed by a purge with inert gas before introducing another reactant onto the substrate in order to prevent gas-phase reactions. In one set of experiments the reactants were supplied separately in the sequence of TDMAT. silane. and ammonia. The Si content of the films remained constant at 18 at.%. and the film growth rate varied little from 0.24 nm per reactant-supply-cycle, even though silane partial pressure varied from 0.002 to 0.1 torr. In the other set of experiments silane and ammonia were simultaneously supplied in the sequence of TDMAT and silane/ammonia. The Si content varied from 3 to 23 at.% as the silane-to-ammonia ratio varied from 0.01 to 10. Atomic layer deposition of Ti-Si-N films allows the precise control of Si content as well as film thickness.

In Situ Real Time Observation of Chemical Vapor Deposition Using an Environmental Transmission Electron Microscope

1995 ◽  
Vol 404 ◽  
Author(s):  
Jeff Drucker ◽  
Renu Sharma ◽  
Karl Weiss ◽  
B. L. Ramakrishna ◽  
John Kouvetakis
Keyword(s):  
Growth Rate ◽  
Electron Beam ◽  
Electron Microscope ◽  
Vapor Deposition ◽  
Electron Beam Irradiation ◽  
Film Growth ◽  
Chemical Vapor ◽  
Beam Irradiation ◽  
Transmission Electron

AbstractMaterial synthesis by chemical vapor deposition (CVD) in a number of material systems has been investigated in real time using an environmental transmission electron microscope (ETEM) with 3.8 Å resolution. Here, we will focus on two metal / insulator systems. Al CVD onto SiO2 from trimethyl amine alane and Au CVD from ethyl (trimethylphosphine) gold (I), also onto SiO2. For Al deposition, dendritic growth was observed for all pressure / substrate temperature combinations investigated for growth on untreated SiO2. Subsequent to reaction of the substrate surface with TiC14, almost immediate continuous Al film growth was observed. Growth rates for the Al film could be measured in situ by monitoring the evolution of the growth front at the Al/vacuum interface. In this system, very little enhancement in the metal film growth rate was observed as a consequence of electron beam irradiation for continuous films grown after TiCl4 pretreatment.. This dramatically contrasts with the case of Au CVD investigated. In this instance, growth rate enhancements of up to 150 times were observed during electron beam irradiation as compared to purely pyrolytic decomposition of the precursor on the insulator surface. This growth rate enhancement decreased monotonically with substrate temperature. We surmise that this effect is related to the ratio of precursor surface residence time prior to ecomposition to the probability of collision from the impinging electron beam.

Evidence for Cooperative Oxidation of Mocvd Precursors Used in BaxSr1‐x TiO3 Film Growth

1996 ◽  
Vol 446 ◽  
Author(s):  
Timothy E. Glassman ◽  
Gautam Bhandari ◽  
Thomas H. Baum
Keyword(s):  
Thermal Decomposition ◽  
Film Growth ◽  
Oxidation Mechanism ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Precise Control ◽  
Carbonate Formation ◽  
Diffraction Patterns ◽  
High Dielectric

AbstractMetal ß‐diketonate complexes are common precursors for chemical vapor deposition (CVD) of a wide variety of thin‐film materials. Liquid delivery CVD has been used to deposit high dielectric constant materials, such as BaxSr1‐xTiO3.[1] This method relies upon volumetric metering of organic soluble precursors, “flash” vaporization to transport the reactants into the gas‐phase and subsequent thermal decomposition onto the heated substrate. This approach enables the precise control of deposited film stoichiometry. In this study, simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to examine the transport and thermal decomposition properties of M(thd)2 (M = Sr, Ba) and Ti(O‐i‐Pr)2(thd)2. In an argon atmosphere, vaporization and transport are observed below 400 °C. In oxidizing atmospheres, such as nitrous oxide and oxygen, decomposition leads to metal carbonate formation as evidenced by both the mass balance and x‐ray diffraction patterns of the residual solids. In the presence of an equimolar amount of the Ti precursor, the formation of carbonates is not observed and oxides are produced at greatly reduced temperatures. Based upon this data, a cooperative oxidation mechanism is proposed which results in “clean” precursor decomposition and BST oxide formation at temperatures near 500 °C.

Microstructural characterization of YBa2Cu3O7-x thin films formed by metalorganic CVD

1991 ◽  
Vol 49 ◽  
pp. 1080-1081
Author(s):  
P. Lu ◽  
W. Huang ◽  
C.S. Chern ◽  
Y.Q. Li ◽  
J. Zhao ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Critical Current Density ◽  
Critical Current ◽  
Current Density ◽  
Film Growth ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Ion Milling ◽  
Conventional Grinding

The YBa2Cu3O7-x thin films formed by metalorganic chemical vapor deposition(MOCVD) have been reported to have excellent superconducting properties including a sharp zero resistance transition temperature (Tc) of 89 K and a high critical current density of 2.3x106 A/cm2 or higher. The origin of the high critical current in the thin film compared to bulk materials is attributed to its structural properties such as orientation, grain boundaries and defects on the scale of the coherent length. In this report, we present microstructural aspects of the thin films deposited on the (100) LaAlO3 substrate, which process the highest critical current density.Details of the thin film growth process have been reported elsewhere. The thin films were examined in both planar and cross-section view by electron microscopy. TEM sample preparation was carried out using conventional grinding, dimpling and ion milling techniques. Special care was taken to avoid exposure of the thin films to water during the preparation processes.

The annealed (0001) α-alumina surface and its influence on thin-film growth

1995 ◽  
Vol 53 ◽  
pp. 336-337
Author(s):  
Michael W. Bench ◽  
Paul G. Kotula ◽  
C. Barry Carter
Keyword(s):  
Electron Microscopy ◽  
Surface Energy ◽  
Film Growth ◽  
Thin Film Growth ◽  
Energy Calculations ◽  
Transmission Electron ◽  
Reflection Electron Microscopy ◽  
Low Energy Electron ◽  
Surface Nature

The growth of semiconductors, superconductors, metals, and other insulators has been investigated using alumina substrates in a variety of orientations. The surface state of the alumina (for example surface reconstruction and step nature) can be expected to affect the growth nature and quality of the epilayers. As such, the surface nature has been studied using a number of techniques including low energy electron diffraction (LEED), reflection electron microscopy (REM), transmission electron microscopy (TEM), molecular dynamics computer simulations, and also by theoretical surface energy calculations. In the (0001) orientation, the bulk alumina lattice can be thought of as a layered structure with A1-A1-O stacking. This gives three possible terminations of the bulk alumina lattice, with theoretical surface energy calculations suggesting that termination should occur between the Al layers. Thus, the lattice often has been described as being made up of layers of (Al-O-Al) unit stacking sequences. There is a 180° rotation in the surface symmetry of successive layers and a total of six layers are required to form the alumina unit cell.

In situ study of electron beam-induced chemical vapor deposition of Au in an environmental TEM

1995 ◽  
Vol 53 ◽  
pp. 256-257
Author(s):  
J. Drucker ◽  
R. Sharma ◽  
J. Kouvetakis ◽  
K.H.J. Weiss
Keyword(s):  
Electron Beam ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Quantum Effect ◽  
Line Drawing ◽  
Chemical Vapor ◽  
Environmental Cell ◽  
Engineering Changes ◽  
Kinetics Of

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.

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