Epitaxial growth of aluminum nitride layers on Si(111) at high temperature and for different thicknesses

1997 ◽  
Vol 12 (1) ◽  
pp. 175-188 ◽  
Author(s):  
F. Malengreau ◽  
M. Vermeersch ◽  
S. Hagège ◽  
R. Sporken ◽  
M. D. Lange ◽  
...  
Keyword(s):  
High Temperature ◽  
Aluminum Nitride ◽  
Epitaxial Growth ◽  
Photoelectron Spectroscopy ◽  
Interfacial Layer ◽  
Depth Profiling ◽  
Lattice Parameter ◽  
Dielectric Constants ◽  
Thin Layers ◽  
Good Surface

We present the epitaxial growth by rf reactive sputtering of aluminum nitride on Si(111) at high temperature. The grain size of the obtained films was sufficient to obtain a good low energy electron diffraction (LEED) pattern from which we determined a lattice parameter of 3.1 Å, indicative of fully relaxed films. The surface of the film was examined in situ by Auger electron spectroscopy (AES); no contamination was detected, with the exception of low levels of oxygen. The film and its interface were studied by high resolution electron energy loss spectroscopy (HREELS), x-ray photoelectron spectroscopy (XPS) depth profiling, and transmission electron microscopy (TEM). Again, a low concentration of oxygen and no carbon contamination were detected by XPS. Three different growth methods were applied to the deposition of aluminum nitride at high temperature. The obtained films were studied in order to determine the influence of the methods on the interface, on the ‘bulk structure’ of the film, and on its surface. Each has been shown to have particular characteristics. The first one, performed at a temperature of 1000 °C, and including a cleaning of the surface by exposure to Al flux, was characterized by an interfacial layer with no long-range order and increasing the interaction between the film and the substrate. The second growth consisting of deposition at the same high temperature has shown a good surface quality for very thin layers (<50 Å ) and the absence of an interfacial layer. The last method, based on a first step of growth at low temperature (700 °C), resulted in good quality thick layers which allowed us to determine the infrared dielectric constants of aluminum nitride by HREELS.

Sub-nm-Scale Depth Profiling of Nitrogen in NO- and N2-Annealed SiO2/4H-SiC(0001) Structures

2019 ◽  
Vol 963 ◽  
pp. 226-229
Author(s):  
Kidist Moges ◽  
Mitsuru Sometani ◽  
Takuji Hosoi ◽  
Takayoshi Shimura ◽  
Shinsuke Harada ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
High Temperature ◽  
Photoelectron Spectroscopy ◽  
Depth Profiling ◽  
Annealing Duration ◽  
Nanometer Scale ◽  
Pure Nitrogen ◽  
X Ray ◽  
Initial Stage

We demonstrated an x-ray photoelectron spectroscopy (XPS)-based technique to reveal the detailed nitrogen profile in nitrided SiO2/4H-SiC structures with sub-nanometer-scale-resolution. In this work, nitric oxide (NO)- and pure nitrogen (N2)-annealed SiO2/4H-SiC(0001) structures were characterized. The measured results of NO-annealed samples with various annealing duration indicate that preferential nitridation just at the SiO2/SiC interfaces (~0.3 nm) proceeds in the initial stage of NO annealing and a longer duration leads to the distribution of nitrogen in the bulk SiO2 within few nanometers of the interface. The high-temperature N2 annealing was found to induce not only SiO2/SiC interface nitridation similarly to NO annealing but also SiO2 surface nitridation.

Epitaxial TaC Films for the Selective Area Growth of SiC

2008 ◽  
Vol 600-603 ◽  
pp. 183-186 ◽  
Author(s):  
Kenneth A. Jones ◽  
T.S. Zheleva ◽  
R.D. Vispute ◽  
Shiva S. Hullavarad ◽  
M. Ervin ◽  
...  
Keyword(s):  
High Temperature ◽  
Surface Morphology ◽  
Epitaxial Growth ◽  
Lattice Parameter ◽  
Selective Area Growth ◽  
Recrystallization Process ◽  
High Temperature Annealing ◽  
Selective Area ◽  
Area Growth ◽  
Lattice Matched

At sufficiently high temperatures PLD deposited TaC films can be grown epitaxially on 4H-SiC (0001) substrates; at lower temperatures the films recrystallize and ball up forming a large number of pinholes. The growth temperature for epitaxy was found to be 1000°C, and it was facilitated by the epitaxial growth of a thin (2 nm) transition layer of hexagonal Ta2C. High temperature annealing produced changes in the surface morphology, caused grain growth, and created pin holes through a recrystallization process in the films deposited at the lower temperatures, while the films deposited at the higher temperatures remained virtually unchanged. Using TEM it is shown that the (0001) basal planes of the hexagonal 4H-SiC and Ta2C phases are aligned, and they were also parallel to the (111) plane in the cubic TaC with the [101] cubic direction being parallel to the hexagonal [2110] hexagonal direction. The Ta2C interlayer most likely is formed because its lattice parameter in the basel plane (3.103 Ǻ) is intermediate between that of the 4H-SiC (3.08 Ǻ) and the TaC (3.150 Ǻ). Given that Al.5Ga.5N is lattice matched to TaC, it could be an excellent substrate for the growth of GaN/AlGaN heterostructures.

Change in Radiative Optical Properties of Tantalum Pentoxide Thin-Films Due to Material Compositional Changes at High Temperature

2005 ◽  
Author(s):  
Ramesh Chandrasekharan ◽  
Shaurya Prakash ◽  
R. I. Masel ◽  
Mark A. Shannon
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Interfacial Layer ◽  
Optimization Technique ◽  
Depth Profiling ◽  
Ta2o5 Film ◽  
Before And After ◽  
Infrared Spectrometer ◽  
Least Squares Optimization ◽  
Deposited Film

Thin films (0.85μm, 3μm) of Ta2O5 deposited on Si and SiO2 were heated to 900°C. Their reflectance in the infrared was measured using an FTIR (Fourier Transform Infrared Spectrometer) equipped with a multiple angle reflectometer before and after exposure to high temperature. An interfacial layer (TaSixOy) formed by the diffusion of Si from the substrate into the deposited film was observed using Auger depth profiling, and the effect of this interfacial layer on the reflectance was measured. Using a least squares optimization technique coupled with an optical admittance algorithm, the multiple angle reflectance data was used to calculate the optical constants of the as deposited Ta2O5 film, crystalline Ta2O5, and the interfacial layer in the 1.6μm to 10μm range. The interfacial layer formed due to exposure to high temperature was found to be more absorptive than the crystalline Ta2O5.

scholarly journals Profiling of the SiO2 - SiC Interface Using X-ray Photoelectron Spectroscopy

2000 ◽  
Vol 640 ◽  
Author(s):  
R. N. Ghosh ◽  
S. Ezhilvalavan ◽  
B. Golding ◽  
S. M. Mukhopadhyay ◽  
N. Mahadev ◽  
...  
Keyword(s):  
High Temperature ◽  
Photoelectron Spectroscopy ◽  
Field Effect ◽  
Depth Profiling ◽  
Interfacial Region ◽  
Thermally Grown Oxides ◽  
X Ray ◽  
Spatially Resolved ◽  
Graphitic Layer ◽  
Field Effect Devices

ABSTRACTThe implementation of SiC based sensors and electronics for operation in chemically harsh, high temperature environments depends on understanding the SiO2/SiC interface in field effect devices. We have developed a technique to fabricate wedge polished samples (angle ∼ 1×10−4 rad) that provides access to the SiO2/SiC interface via a surface sensitive probe such as xray photoelectron spectroscopy (XPS). Lateral scanning along the wedge is equivalent to depth profiling. Spatially resolved XPS images of the O 1s and Si 2p core levels were obtained of the interfacial region. Samples consist of device-quality thermally grown oxides on 4H-SiC single crystal substrates. The C 1s spectrum suggests the presence of a graphitic layer on the nominally bare SiC surface following thermal oxidation.

Silicide Formation for Ni and Pd Bilayers on Si(100) Substrates

2001 ◽  
Vol 670 ◽  
Author(s):  
Xin-Ping Qu ◽  
C. Detavernier ◽  
R. L. Van Meirhaeghe ◽  
F. Cardon
Keyword(s):  
Photoelectron Spectroscopy ◽  
Depth Profiling ◽  
Lattice Parameter ◽  
Nucleation Theory ◽  
Nucleation Temperature ◽  
Silicide Formation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Classic Nucleation Theory ◽  
Entropy Effect

ABSTRACTThe silicide formation for Ni/Pd and Pd/Ni bilayers on Si(100) substrates was investigated. X-ray diffraction and photoelectron spectroscopy (XPS) depth profiling have been applied to study the phase formation of the silicide. We found that with addition of Pd into Ni/Si, a uniform layer of ternary Ni1−xPdxSi layer formed and kept stable for a wide temperature range. The lattice parameter of Ni1−xPdxSi as a function of Pd addition was calculated. The nucleation temperature of NiSi2 was delayed due to the addition of Pd. The higher the Pd addition, the larger the increase in NiSi2 nucleation temperature. We also studied the effect on the addition of Ni to the Pd/Si reaction. For pure Pd/Si reaction PdSi nucleated from Pd2Si at 750°C or above. For Ni/Pd/Si reaction, Pd2Si changed to Ni1−xPdxSi at temperature lower than 750°C due to the incorporation of Ni. The phenomena were explained by classic nucleation theory taking into account the effect of mixing entropy effect.

Change in Radiative Optical Properties of Ta2O5 Thin Films due to High-Temperature Heat Treatment

2006 ◽  
Vol 129 (1) ◽  
pp. 27-36 ◽  
Author(s):  
Ramesh Chandrasekharan ◽  
Shaurya Prakash ◽  
Mark A. Shannon ◽  
R. I. Masel
Keyword(s):  
Thin Films ◽  
Heat Treatment ◽  
High Temperature ◽  
Interfacial Layer ◽  
Optimization Technique ◽  
Depth Profiling ◽  
High Temperature Heat Treatment ◽  
Temperature Heat ◽  
Before And After ◽  
Temperature Heat Treatment

Thin films (0.85μm, 3μm) of Ta2O5 deposited on Si and SiO2 were heated to 900°C. Their reflectance in the infrared was measured using a Fourier transform infrared spectrometer equipped with a multiple angle reflectometer before and after exposure to the high-temperature heat treatment. An interfacial layer (TaSixOy) formed by the diffusion of Si from the substrate into the deposited film was observed using Auger depth profiling, and the effect of this interfacial layer on the reflectance was measured. Using a least squares optimization technique coupled with an optical admittance algorithm, the multiple angle reflectance data were used to calculate the optical constants of the as deposited Ta2O5 film, crystalline Ta2O5, and the interfacial layer in the 1.6 to 10μm range. The interfacial layer formed due to exposure to high temperature was found to be more absorptive than the crystalline Ta2O5.

Preferential Sputtering of Ni3Al Single Crystals Studied Using Atom-Probe Field-Ion Microscopy and XPS

1981 ◽  
Vol 39 ◽  
pp. 16-17
Author(s):  
M.P. Thomas ◽  
A.R. Waugh ◽  
M.J. Southon ◽  
Brian Ralph
Keyword(s):  
Single Crystals ◽  
Photoelectron Spectroscopy ◽  
Surface Composition ◽  
Depth Profiling ◽  
Analytical Techniques ◽  
Atom Probe ◽  
Probe Field ◽  
Preferential Sputtering ◽  
Argon Ion Bombardment ◽  
Argon Ion

It is well known that ion-induced sputtering from numerous multicomponent targets results in marked changes in surface composition (1). Preferential removal of one component results in surface enrichment in the less easily removed species. In this investigation, a time-of-flight atom-probe field-ion microscope A.P. together with X-ray photoelectron spectroscopy XPS have been used to monitor alterations in surface composition of Ni3Al single crystals under argon ion bombardment. The A.P. has been chosen for this investigation because of its ability using field evaporation to depth profile through a sputtered surface without the need for further ion sputtering. Incident ion energy and ion dose have been selected to reflect conditions widely used in surface analytical techniques for cleaning and depth-profiling of samples, typically 3keV and 1018 - 1020 ion m-2.

AEM of reaction-bonded SiC

1992 ◽  
Vol 50 (1) ◽  
pp. 344-345
Author(s):  
K Das Chowdhury ◽  
R. W. Carpenter ◽  
W. Braue
Keyword(s):  
Mechanical Properties ◽  
Phase Transformation ◽  
High Temperature ◽  
Epitaxial Growth ◽  
Liquid Silicon ◽  
Structural Ceramic ◽  
Few Data

Research on reaction-bonded SiC (RBSiC) is aimed at developing a reliable structural ceramic with improved mechanical properties. The starting materials for RBSiC were Si,C and α-SiC powder. The formation of the complex microstructure of RBSiC involves (i) solution of carbon in liquid silicon, (ii) nucleation and epitaxial growth of secondary β-SiC on the original α-SiC grains followed by (iii) β>α-SiC phase transformation of newly formed SiC. Due to their coherent nature, epitaxial SiC/SiC interfaces are considered to be segregation-free and “strong” with respect to their effect on the mechanical properties of RBSiC. But the “weak” Si/SiC interface limits its use in high temperature situations. However, few data exist on the structure and chemistry of these interfaces. Microanalytical results obtained by parallel EELS and HREM imaging are reported here.

CBED analysis of impurity distributions in AlN

1990 ◽  
Vol 48 (4) ◽  
pp. 214-215
Author(s):  
Daniel Callahan ◽  
G. Thomas
Keyword(s):  
Aluminum Nitride ◽  
Bulk Material ◽  
Strong Dependence ◽  
Lattice Parameter ◽  
Promising Technique ◽  
Nitride Ceramics ◽  
Surface Phases ◽  
Convergent Beam ◽  
Oxygen Impurities

Oxygen impurities may significantly influence the properties of nitride ceramics with a strong dependence on the microstructural distribution of the impurity. For example, amorphous oxygen-rich grain boundary phases are well-known to cause high-temperature mechanical strength degradation in silicon nitride whereas solutionized oxygen is known to decrease the thermal conductivity of aluminum nitride. Microanalytical characterization of these impurities by spectral methods in the AEM is complicated by reactions which form oxygen-rich surface phases not representative of the bulk material. Furthermore, the impurity concentrations found in higher quality ceramics may be too low to measure by EDS or PEELS. Consequently an alternate method for the characterization of impurities in these ceramics has been investigated.Convergent beam electron diffraction (CBED) is a promising technique for the study of impurity distributions in aluminum nitride ceramics. Oxygen is known to enter into stoichiometric solutions with AIN with a consequent decrease in lattice parameter.

High-Temperature Instability of A Cr2Nb-Nb(Cr) Microlaminate Composite

1996 ◽  
Vol 54 ◽  
pp. 374-375
Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Aircraft Engine ◽  
Lattice Parameter ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Cross Sectional ◽  
Bcc Structure

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.

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