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 Properties of Undoped 6H- and 4H-SiC Bulk Crystals Grown by Halide Chemical Vapor Deposition

2006 ◽  
Vol 527-529 ◽  
pp. 625-628
Author(s):  
Hun Jae Chung ◽  
Sung Wook Huh ◽  
A.Y. Polyakov ◽  
Saurav Nigam ◽  
Qiang Li ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Boron Concentration ◽  
Secondary Ion Mass Spectrometry ◽  
Nitrogen Concentration ◽  
Chemical Vapor ◽  
Bulk Crystals ◽  
Hall Effect Measurements ◽  
Site Competition ◽  
Secondary Ion

Undoped 6H- and 4H-SiC crystals were grown by Halide Chemical Vapor Deposition (HCVD). Concentrations of impurities were measured by various methods including secondary-ion-mass spectrometry (SIMS). With increasing C/Si ratio, nitrogen concentration decreased and boron concentration increased as expected for the site-competition effect. Hall-effect measurements on 6H-SiC crystals showed that with the increase of C/Si ratio from 0.06 to 0.7, the Fermi level was shifted from Ec-0.14 eV (nitrogen donors) to Ev+0.6 eV (B-related deep centers). Crystals grown with C/Si > 0.36 showed high resistivities between 1053 and 1010 4cm at room temperature. The high resistivities are attributed to close values of the nitrogen and boron concentrations and compensation by deep defects present in low densities.

Advances in the Characterization of Compositionally-graded Layers in Amorphous Semiconductor Solar Cells by Real Time Spectroellipsometry

1996 ◽  
Vol 420 ◽  
Author(s):  
R. W. Collins ◽  
Sangbo Kim ◽  
Joohyun Koh ◽  
J. S. Burnham ◽  
Lihong Jiao ◽  
...  
Keyword(s):  
Solar Cells ◽  
Real Time ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Interface Layer ◽  
Open Circuit ◽  
Amorphous Semiconductor ◽  
Deposition Parameters ◽  
Gas Flow Ratio ◽  
Graded Layers

AbstractWe have developed a real time spectroellipsometry data analysis procedure that allows us to characterize compositionally- graded amorphous semiconductor alloy thin films prepared by plasma-enhanced chemical vapor deposition (PECVD). As an example, we have applied the analysis to obtain the depth-profile of the optical gap and alloy composition with ≤15 Å resolution for a hydrogenated amorphous silicon-carbon alloy (a-Si1−xCx:H) film prepared by continuously varying the gas flow ratio z=[CH4]/{[CH4]+[SiH4]} in the PECVD process. The graded layer has been incorporated at the p/i interface of widegap a-Si1−xCx:H (x∼0.05) p-i-n solar cells, and consistent improvements in open-circuit voltage have been demonstrated. The importance of the graded-layer characterization is the ability to relate improvements in device performance directly to the physical properties of the interface layer, rather to the deposition parameters with which they were prepared.

Copper Films Prepared by Metal Organic Chemical Vapor Deposition (MOCVD) Process Using Copper (Acetylacetonate) and Water Vapor as Reactants: The Impact of Water Vapor

1992 ◽  
Vol 282 ◽  
Author(s):  
Yu-Neng Chang
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Organic Chemical ◽  
Gas Flow Rate ◽  
Cu Films ◽  
Metal Organic ◽  
Carrier Gas Flow ◽  
Organic Chemical Vapor Deposition

ABSTRACTBy using the strong reductive potential of copper acetylacetone (Cu(acac)2) when Cu(acac)2) was thermally decomposed, copper metal films were prepared by metal organic chemical vapor deposition (MOCVD) process using sublimed Cu(acac)2 vapor and water vapor as reactants, at one atmosphere pressure. According to thermodynamic calculations, Cu films could be prepared by MOCVD process with a high ratio of partial pressures for water vapor and Cu(acac)2 vapor (PH2O/Pcu(acac)2>30) In this paper, the impacts of MOCVD processing parameters such as watervapor partial pressure, total carrier gas flow rate, and precursor partial pressure on film composition and microstructure were investigated. Deposition temperature is the primary processing parameter affecting film stoichiometry. In a specific deposition temperature window, from 370°C to 400°C, polycrystalline Cu films with Cu [111] preferential orientation were deposited. ER and XRD results indicated that films deposited at temperature lower than 350°C contain copper oxide phase with poor crystal structure. By comparing the values of X-ray Auger Electron Spectroscopy (XAES) and Auger parameter (αAu) from photoelectrons of Cu films and standards from reference compounds, die principle oxidation state of copper in these films was determined as Cu(0). The deposition results indicated that a water vapor partial pressure above 10 torr is necessary to produce Cu films. As indicated by SEM, Increasing the carrier gas flow rate, above 600 sccm, can reduce the average temperature profile in the thermal boundary layer above the substrate surface, retard the gas phase reaction rate, presumably eliminate the homogeneous nucleation, and deposit smooth Cu films.

Some Observations on the Electrical Characterization of the Heteroepitaxially Grown Cubic SiC

1989 ◽  
Vol 162 ◽  
Author(s):  
B. Molnar ◽  
G. Kelner
Keyword(s):  
Activation Energy ◽  
Secondary Ion Mass Spectrometry ◽  
Nitrogen Concentration ◽  
Electrical Characterization ◽  
Impurity Band ◽  
Thin Layers ◽  
Si Substrates ◽  
Nitrogen Concentrations ◽  
Band Conduction

ABSTRACTThis paper re-examines the electrical characterization of thin layers of cubic SiC, grown on (100) Si substrates. The resistivity and Hall coefficient for undoped SiC layers were measured between 10 K and 500 K. Electron spin resonance (ESR) and secondary ion mass spectrometry (SIMS) were used to identify and determine the nitrogen concentrations, which were higher than 1017/cm3. In all the samples examined the Hall measurements indicated impurity band conduction. Therefore, the temperature dependence of the resistivity has been used to derive an activation energy el. The value of el found to be in the range of 0.032–0.025 eV. The observed decrease in activation energy has been correlated with an increase in nitrogen concentration. The presence of substantial nitrogen leads to impurity band conduction and it is the most likely reason for the conflicting values reported for the dominant donor ionization energy by Hall and PL measurements.

Dependence of PECVD Silicon Oxynitride Properties on Deposition Parameters

1988 ◽  
Vol 131 ◽  
Author(s):  
Aubrey L. Helms ◽  
Robert M. Havrilla
Keyword(s):  
Gas Flow ◽  
Chemical Vapor ◽  
Silicon Oxynitride ◽  
Gas Flow Rate ◽  
Process Gas ◽  
Deposition Parameters ◽  
Chemical Vapor Deposited ◽  
Passivation Layers ◽  
Parallel Plate Reactor ◽  
Deposition Conditions

ABSTRACTThe properties of Plasma Enhanced Chemical Vapor Deposited (PECVD) silicon oxynitride thin films were determined for a variety of deposition conditions. The films were characterized with respect to stress, refractive index, deposition rate, hydrogen content, dielectric constant, and uniformity. The films were deposited in an Electrotech ND6200 parallel plate reactor using a silane - ammonia - nitrous oxide process gas chemistry. Deposition parameters which were investigated include process gas flow rate, power, and total pressure. The possible application of these films as both inter-layer and final passivation layers for use on GaAs ICs will be discussed.

Intense UV-Visible-IR Adjustable Photoluminescence from Silicon-rich Oxynitride Layers Prepared by Plasma Enhanced Chemical Vapor Deposition

1999 ◽  
Vol 560 ◽  
Author(s):  
Zingway Pei ◽  
Y.J. Chung ◽  
H.L. Hsiao ◽  
H.L. Hwang
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
Gas Flow ◽  
Chemical Vapor ◽  
Silicon Clusters ◽  
Process Gas ◽  
Gas Flow Ratio ◽  
Uv Visible

ABSTRACTThe intense UV-visible-IR adjustable light emissions from silicon-rich oxynitride thin films without any thermal annealing were observed at room temperature under a 325 nm He-Cd laser excitation. The silicon-rich oxynitride thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) with the mixture of 5% Ar diluted silane and nitrous oxide gases. The strong naked-eye recognizable photoluminescence (blue-white-red) could be adjusted by changing the process gas flow ratio τ =([SiH4]/[N20]). To the best of our knowledge, intense and adjustable UV-blue light emissions in the as-deposited thin films are first reported in this work. The Fourier Transform infrared (FTIR) spectroscopy was applied to investigate the microstructure-bonding configurations, in which silicon polysilane related bonding at 830-890 cm' present that silicon complex, exists along with the Si-O-Si bonding. X-ray photoelectron spectroscopy was used to investigate the binding configuration, the binding energy of Si 2p appearing at 99.3 eV was indicative of formation of the silicon clusters. As a consequence, we suppose that the visible-IR lights emissions might possible be strongly related to silicon clusters formation in the films and the intense UV emissions might come from the oxygen-related defects.

Discussion on microstructure of chemical-vapor-deposited TiN films based on the calculated gaseous concentration distribution in the reactor

1995 ◽  
Vol 10 (11) ◽  
pp. 2801-2807 ◽  
Author(s):  
Noboru Yoshikawa ◽  
Atsushi Kikuchi
Keyword(s):  
Partial Pressure ◽  
Flow Rate ◽  
Gas Flow ◽  
Tubular Reactor ◽  
Chemical Vapor ◽  
Axial Direction ◽  
Preferred Orientation ◽  
Upstream Region ◽  
Gas Flow Rate ◽  
Tin Films

TiN films were ehemical-vapor-deposited on the inner wall of a tubular reactor. Films deposited in the upstream region of the reactor consisted of small and sharp crystals with (111)-preferred orientation or random orientation. On the other hand, films deposited in the downstream region or at lower partial pressure of TiCl4 consisted of columnar crystals with (110)-preferred orientation, having polyhedral shapes on the surface. For the films deposited under different conditions at different axial positions, relationships were investigated among the temperature, the calculated concentrations on the substrate, and the degree of preferred orientation of the films. As a result, it was shown that formation of films with (110)-preferred orientation is related to the conditions of high temperature and low partial pressure of TiCl4. Films deposited at the higher gas flow rate had lower degrees of (110)-preferred orientation. Decrease in partial pressure of TiCl4 along the axial direction in the reactor was calculated to be smaller at higher gas flow rate, and provided suitable conditions for deposition of films having small and sharp crystals.

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