High-temperature electrical behavior of nanocrystalline and microcrystalline diamond films

2008 ◽  
Vol 23 (10) ◽  
pp. 2774-2786 ◽  
Author(s):  
N. Govindaraju ◽  
D. Das ◽  
R.N. Singh ◽  
P.B. Kosel
Keyword(s):  
High Temperature ◽  
Gas Phase ◽  
Room Temperature ◽  
Microelectromechanical Systems ◽  
Nitrogen Concentration ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Electrical Behavior ◽  
Nitrogen Concentrations ◽  
New Applications

Chemical vapor deposition of diamond has opened up new applications in microelectronics, microelectromechanical systems (MEMS), and coating technologies. This paper compares and contrasts the high-temperature electrical behavior of microcrystalline versus nanocrystalline diamond films. Through-thickness current–voltage characteristics between room temperature and 823 K are presented for a series of films synthesized with different gas phase concentrations of nitrogen and argon. One set of samples was characterized by measurements between room temperature and 823 K and a second set by two-step thermal cycling from room temperature to 573 and 823 K. It was found that with increasing nitrogen concentration (up to 0.1% N2), the resistivity slightly increased followed by a decrease at higher concentrations. Activation energies and barrier heights were in general lower for the more defective films. These results in conjunction with material characterization indicated that more defective diamond films were synthesized at higher nitrogen concentrations in the gas phase.

Diamond Films: Recent Developments

MRS Bulletin ◽  
1998 ◽  
Vol 23 (9) ◽  
pp. 16-21 ◽  
Author(s):  
Dieter M. Gruen ◽  
Ian Buckley-Golder
Keyword(s):  
High Temperature ◽  
Integrated Circuits ◽  
Nuclear Power ◽  
Large Scale ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Large Area ◽  
Technical Problems ◽  
Practical Applications ◽  
Single Crystal Diamond

Carbon in the form of diamond is the stuff of dreams, and the image of the diamond evokes deep and powerful emotions in humans. Following the successful synthesis of diamond by high-pressure methods in the 1950s, the startling development of the low-pressure synthesis of diamond films in the 1970s and 1980s almost immediately engendered great expectations of utility. The many remarkable properties of diamond due in part to its being the most atomically dense material in the universe (hardness, thermal conductivity, friction coefficient, transparency, etc.) could at last be put to use in a multitude of practical applications. “The holy grail”—it was realized early on—would be the development of large-area, doped, single-crystal diamond wafers for the fabrication of high-temperature, extremely fast integrated circuits leading to a revolution in computer technology.Excitement in the community of chemical-vapor-deposition (CVD) diamond researchers, funding agencies, and industrial companies ran high in expectation of early realization for many of the commercial goals that had been envisioned: tool, optical, and corrosion-resistant coatings; flat-panel displays; thermomanagement for electronic components, etc. Market projection predicting diamond-film sales in the billions of dollars by the year 2000 was commonplace. Hopes were dashed when these optimistic predictions ran up against the enormous scientific and technical problems that had to be overcome in order for those involved to fully exploit the potential of diamond. This experience is not new to the scientific community. One need only remind oneself of the hopes for cheap nuclear power or for high-temperature superconducting wires available at hardware stores to realize that the lag between scientific discoveries and their large-scale applications can be very long. Diamond films are in fact being used today in commercial applications.

Thermoelectric Properties of Er-doped InGaN Alloys for High Temperature Applications

2011 ◽  
Vol 1325 ◽  
Author(s):  
K. Aryal ◽  
I. W. Feng ◽  
B. N. Pantha ◽  
J. Li ◽  
J. Y. Lin ◽  
...  
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Metal Organic ◽  
Er Doped ◽  
Organic Chemical Vapor Deposition ◽  
Co Doped ◽  
Ingan Alloys ◽  
Temperature Applications

ABSTRACTThermoelectric (TE) properties of erbium-silicon co-doped InxGa1-xN alloys (InxGa1-xN: Er + Si, 0≤x≤0.14), grown by metal organic chemical vapor deposition, have been investigated. It was found that doping of InGaN alloys with Er atoms of concentration, N[Er] larger than 5x1019 cm-3, has substantially reduced the thermal conductivity, κ, in low In content InGaN alloys. It was observed that κ decreases as N[Er] increases in Si co-doped In0.10Ga0.90N alloys. A room temperature ZT value of ~0.05 was obtained in In0.14Ga0.86N: Er + Si, which is much higher than that obtained in un-doped InGaN with similar In content. Since low In content InGaN is stable at high temperatures, these Er+Si co-doped InGaN alloys could be promising TE materials for high temperature applications.

Synthesis of Diamond by Laser-Induced CVD

1986 ◽  
Vol 75 ◽  
Author(s):  
K. Kitahama ◽  
K. Hirata ◽  
H. Nakamatsu ◽  
S. Kawai ◽  
N. Fujimori ◽  
...  
Keyword(s):  
Gas Phase ◽  
Electronic Excitation ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Laser Power Density ◽  
Adsorbate Layer ◽  
Irradiation Geometry ◽  
Arf Excimer Laser ◽  
Reflection Electron Diffraction ◽  
Beam Deposition

AbstractSynthesis of diamond thin-films has been tried by an ArF excimer laser-induced chemical vapor deposition (LCVD) technique, using acetylene diluted with hydrogen as a source gas and a silicon wafer as a substrate. In these experiments, irradiation geometry, substrate temperature and laser power density were varied. Upon irradiation by a focused laser beam, deposition of diamond on substrates heated above 400°Cwas observed, and was confirmed by reflection electron diffraction (RED) photographs. Homogeneity of the diamond films was improved by irradiation parallel to the substrate. These facts suggest that the formation of diamond proceeds through multiple photon decomposition of the reactant gas, and that electronic excitation of gas phase rather than that of substrate or adsorbate layer is essential to form diamond.

IR Diagnostics of MOCVD Reaction Chemistry

1992 ◽  
Vol 282 ◽  
Author(s):  
Bruce H. Weiller
Keyword(s):  
Reaction Time ◽  
Gas Phase ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Flow Tube ◽  
Tube Reactor ◽  
Ftir Spectrometer ◽  
Ir Diagnostics ◽  
Trimethyl Aluminum ◽  
Phase Chemical

ABSTRACTThe gas-phase chemical reactions in the Metallorganic Chemical Vapor Deposition (MOCVD) of A1N and TiN have been studied using IR spectroscopy. The products formed from the reaction of trimethyl aluminum (TMA) and NH3 were compared to those from the reaction of TMAwith NF3 using a static gas-phase IR cell. Reaction with NH3 is rapid at 25 °C, and the IR spectrum of the product is consistent with the acid-base adduct (CH3)3Al-NH3. At 25 °C, no reaction between TMA and NF3 was observed. However, at 58 °C a slow reaction occurredto give (CH3)2AlF. The reaction of Ti(N(CH3)2)4 with NH3 was also studied using a flow-tube reactor with a sliding injector port that provides control over the reaction time between two reactive flows. By monitoring the disappearance of Ti(N(CH3)2)4 as a function of NH3 partial pressure and reaction time, we have obtained a preliminary estimate of the rate constant as ∼ 10−16 cm3 molecule−1 s−1 at 25 °C. This result confirms that the reaction is rapid even at room temperature and demonstrates the utility of the flow-tube reactor and FTIR spectrometer for studies of MOCVD chemistry.

Phase Transformation of Nanocrystalline Diamond Films: Effect of Methane Concentration

2020 ◽  
Vol 831 ◽  
pp. 127-131
Author(s):  
S.Tipawan Khlayboonme ◽  
Thowladda Warawoot
Keyword(s):  
Phase Transformation ◽  
Gas Phase ◽  
Electron Density ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Graphite Phase ◽  
Diamond Phase ◽  
Nanocrystalline Diamond Films

Ultra-nanocrystalline diamond films were prepared by a microwave plasma-enhanced chemical vapor deposition reactor using CH4/H2 gas mixture with a power as low as 650 W. The effects of CH4 concentration on nanostructure of the films and gas-phase species in plasma were investigated. The CH4 concentrations of 1.5%, 3.0%, 3.5%, and 4.0% were used and balanced with H2 to a total flow rate of 200 sccm. Morphology and composition of the films were characterized by SEM, Raman spectroscopy and Auger spectroscopy. The gas-phase species and electron density in the plasma were explored by optical emission spectroscopy and plasma-impedance measurement. The increasing CH4 concentration from 1.5% to 4.0% increased C2Hx species and decreased electron density. Phase of the film transform from nano- into ultranano- diamond phase but the growth rate revealingly decreased from 300 to 210 nm/h. Raman spectra indicate the higher CH4 concentration promted phase of the film transiton from NCD to UNCD. While Auger spectra revealed that UNCD film deposited with 4.0%CH4 was composed of 90.52% diamond phase but only 9.48% of graphite phase. The relation between phase transformation of the films and growth mechnism controlled by gas-phase species in the plasma will be dissused.

In Situ Measurement of Nitrogen during Growth of 4H-SiC by CVD

2007 ◽  
Vol 556-557 ◽  
pp. 125-128 ◽  
Author(s):  
Brenda L. VanMil ◽  
Kok Keong Lew ◽  
Rachael L. Myers-Ward ◽  
Ronald T. Holm ◽  
D. Kurt Gaskill ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Real Time ◽  
Mass Spectrometer ◽  
Gas Flow ◽  
Secondary Ion Mass Spectrometry ◽  
Nitrogen Concentration ◽  
Chemical Vapor ◽  
Real Time Analysis ◽  
Process Gas ◽  
Nitrogen Concentrations

Real-time analysis of downstream nitrogen process-gas flows during 4H-SiC growth is reported. A Hiden Analytical HPR-20 quadrupole mass-spectrometer (QMS) was used to measure the process gas composition in the gas-stream of a hot-wall chemical vapor deposition (CVD) reactor. Using the 28 amu peak, it was found that the nitrogen partial pressure measured by the mass spectrometer directly correlates to the expected partial pressure of nitrogen in the process cell based on input flows. Two staircase doping samples were grown to track doping variations. The nitrogen mass flow was varied and corresponded to doping levels ranging from 1x1015 cm-3 to 8x1018 cm-3. Electron and nitrogen concentrations in the epilayers were measured by capacitancevoltage (CV) profiling and secondary ion mass spectrometry (SIMS), respectively. These efforts show real-time QMS monitoring is effective during growth for determining relative changes in nitrogen concentration in the gas flow, and thus, the level of nitrogen incorporation into the growing layer.

ELECTRICAL AND MAGNETIC PROPERTIES OF NANOCYSTALLINE DIAMOND FILMS

2005 ◽  
Vol 19 (01n03) ◽  
pp. 611-613
Author(s):  
K. J. LIAO ◽  
W. L. WANG ◽  
X. L. SUN ◽  
J. W. LU ◽  
C. Y. KONG
Keyword(s):  
Magnetic Field ◽  
Vapor Deposition ◽  
Room Temperature ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Geometrical Size ◽  
Electrical And Magnetic Properties ◽  
P Type ◽  
Hot Filament ◽  
The Magnetic Field

The magneto resistive effect in nanocystalline diamond films was investigated at room temperature. The nanocystalline diamond films on silicon were deposited by hot filament chemical vapor deposition. The experimental results showed that a striking magneto resistive effect in p-type doped nanocystalline diamond films was observed. The relative changes in the resistivity of the films were about 0.3 at room temperature under the magnetic field of 5T, and increased with decreasing the geometrical size of the devices. It was found that the magneto resistive effect in the nanocystalline diamond films was less than that of epitaxial diamond films. This was ascribed to a large number of grain boundaries. The results are discussed in detail.

Influence of the Gas Phase Composition on Nanocrystalline Diamond Films Prepared by MWCVD

2005 ◽  
Vol 23 ◽  
pp. 31-34 ◽  
Author(s):  
Cyril Popov ◽  
Miroslav Jelínek ◽  
S. Boycheva ◽  
V. Vorlícek ◽  
Wilhelm Kulisch
Keyword(s):  
Phase Composition ◽  
Gas Phase ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Plasma Chemical ◽  
Plasma Chemical Vapor Deposition ◽  
Bonding Structure

Nanocrystalline diamond (NCD) films have been prepared by microwave plasma chemical vapor deposition (MWCVD) from methane/nitrogen mixtures, and the influence of the gas phase composition on the basic properties of the films (composition, morphology, topography, crystallinity and bonding structure) was investigated.

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