Lattice-Matching Growth of InGaAIN Systems

1995 ◽  
Vol 395 ◽  
Author(s):  
Takashi Matsuoka
Keyword(s):  
High Performance ◽  
Ternary Alloys ◽  
Rocking Curve ◽  
Lattice Matching ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients ◽  
P Type ◽  
Gan Film

ABSTRACTThe development and device applications of the InGaAIN system have progressed dramatically with improvements in crystalline quality by achieved through a buffer layer, the realization of p-type doping, and the growth of ternary alloys. As a substrate, sapphire is mainly used for epitaxial growth because of the lack of a GaN bulk crystal. However, many cracks in GaN film can still be observed and its X-ray rocking curve width is less than 100 arc seconds. This is are thought to be due to the lattice constants and thermal expansion coefficients of GaN and sapphire differ by 13.8% and by -34.2%, respectively. These values are extremely large in comparison with the corresponding values for InP and GaAs. Lattice-matching growth thus remains a basic problem in growing the high-quality epitaxial films necessary for high-performance devices.This paper reviews attempts at lattice-matching growth. Lattice-matching growth of InGaN on a house-made ZnO substrate and near-lattice-matching growth of GaN on SiC and NdGaO3 substrates have been proposed and performed, and the effects of lattice-matching have been confirmed. Various types of surface planes commercially available sapphire substrates are also discussed.

Defects in β-SiC thin films grown on α-SiC substrates

1988 ◽  
Vol 46 ◽  
pp. 568-569
Author(s):  
Karren L. More
Keyword(s):  
Thin Films ◽  
Semiconductor Device ◽  
Lattice Mismatch ◽  
Chemical Vapor ◽  
Substrate Material ◽  
Growth Interface ◽  
Si Substrates ◽  
Thermal Expansion Coefficients ◽  
Device Applications ◽  
Expansion Coefficients

Beta-SiC is an ideal candidate material for use in semiconductor device applications. Currently, monocrystalline β-SiC thin films are epitaxially grown on {100} Si substrates by chemical vapor deposition (CVD). These films, however, contain a high density of defects such as stacking faults, microtwins, and antiphase boundaries (APBs) as a result of the 20% lattice mismatch across the growth interface and an 8% difference in thermal expansion coefficients between Si and SiC. An ideal substrate material for the growth of β-SiC is α-SiC. Unfortunately, high purity, bulk α-SiC single crystals are very difficult to grow. The major source of SiC suitable for use as a substrate material is the random growth of {0001} 6H α-SiC crystals in an Acheson furnace used to make SiC grit for abrasive applications. To prepare clean, atomically smooth surfaces, the substrates are oxidized at 1473 K in flowing 02 for 1.5 h which removes ∽50 nm of the as-grown surface. The natural {0001} surface can terminate as either a Si (0001) layer or as a C (0001) layer.

Temperature dependence of lattice constants of the rare-earth hexaborides EuB6and GdB6

2001 ◽  
Vol 34 (2) ◽  
pp. 208-209 ◽  
Author(s):  
Yasuhiko Takahashi ◽  
Masayoshi Fujimoto ◽  
Masashi Tsuchiko ◽  
Ken-Ichi Ohshima
Keyword(s):  
Rare Earth ◽  
Temperature Dependence ◽  
Linear Thermal Expansion ◽  
X Ray ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Temperature Dependences ◽  
Expansion Coefficients ◽  
Ray Patterns ◽  
The Rare Earth

The temperature dependences of the lattice constants of single crystals of the rare-earth hexaborides EuB6and GdB6were determined by analysing the low-temperature X-ray patterns. The lattice constant decreases monotonously with decreasing temperature. The linear thermal expansion coefficients for the two compounds were also obtained by analysing the temperature dependence of the lattice constants.

Variations of lattice constants and thermal expansion coefficients of indium at high pressure and high temperature

2018 ◽  
Vol 38 (4) ◽  
pp. 406-413 ◽  
Author(s):  
Yusaku Takubo ◽  
Hidenori Terasaki ◽  
Tadashi Kondo ◽  
Shingo Mitai ◽  
Seiji Kamada ◽  
...  
Keyword(s):  
High Pressure ◽  
Thermal Expansion ◽  
High Temperature ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

Crystal Distortion Associated with Magnetic Ordering in Alpha Iron Oxide and Manganese Carbonate

1972 ◽  
Vol 16 ◽  
pp. 390-395 ◽  
Author(s):  
W. S. McCain ◽  
D. L. Albright
Keyword(s):  
Thermal Expansion ◽  
Lattice Constant ◽  
Room Temperature ◽  
Axial Ratio ◽  
Manganese Carbonate ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients ◽  
Position Parameter ◽  
Oxygen Distance

AbstractThe magnetic crystal disrortion of weakly ferromagnetic α-Fe2O3 was investigated by x-ray diffraction techniques. Here crystal distortion is taken as the temperature dependent changes of lattice constants and thermal expansion coefficients. Moreover, the oxygen position parameter and the carbon-oxygen distance of MnCO3 were determined.The lattice constants and thermal expansion coefficients of α-Fe2O3 were measured from room temperature down to 243°K. The crystal distortion, as measured by the changes in lattice constants, thermal expansion coefficients and axial ratio, was found to be highly anisotropic. The co hexagonal lattice constant was influenced very slightly by magnetic distortion; it changed only by 0.01 percent between room temperature and the Morin temperature of 254°K. On the other hand, the ao lattice constant changes by 0.11 percent between room temperature and the Morin temperature. The thermal expansion coefficients of the lattice constants showed a similar contrast. The co coefficient was found to be independent of temperature from room temperature down to the Morin temperature. However, in the same temperature range, the ao coefficient showed an anomalous increase with decreasing temperature. In addition, the ao coefficient showed an infinite discontinuity at the Morin temperature.The change in the axial ratio with temperature suggests that the net weak ferromagnetic moment of α-Fe2O3 reaches a maximum at 275°K.The oxygen position parameter, x, in MnCO3 as determined from two reflections has a value of 0.2702 ± 0.001. The carbon-oxygen distance as calculated from the lattice constants and the oxygen position parameter is 1.29 ±0.002 Å. This value is another confirmation of the Pauling theory of the resonating carbonate structure.

High-performance SrNb0.1Co0.9−xFexO3−δperovskite cathodes for low-temperature solid oxide fuel cells

2014 ◽  
Vol 2 (37) ◽  
pp. 15454-15462 ◽  
Author(s):  
Yinlong Zhu ◽  
Jaka Sunarso ◽  
Wei Zhou ◽  
Shanshan Jiang ◽  
Zongping Shao
Keyword(s):  
Solid Oxide Fuel Cells ◽  
Peak Power ◽  
High Performance ◽  
Reduction Reaction ◽  
Solid Oxide ◽  
Oxide Fuel ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Orr Activity ◽  
Expansion Coefficients

A novel family of perovskites, SrNb0.1Co0.9−xFexO3−δ(SNCF, 0.1 ≤x≤ 0.5), shows not only high oxygen reduction reaction (ORR) activity at operating temperatures below 600 °C (e.g.peak power density of 1587 mW cm−2at 600 °C) but also low thermal expansion coefficients (TECs) and improved CO2resistivity.

Measured and calculated thermoelastic properties of supersaturated fcc Ni(Al) and Ni(Zr) solid solutions

1998 ◽  
Vol 13 (6) ◽  
pp. 1717-1723 ◽  
Author(s):  
J. Bøttiger ◽  
N. Karpe ◽  
J. P. Krog ◽  
A. V. Ruban
Keyword(s):  
Solid Solutions ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Debye Temperatures ◽  
Expansion Coefficients ◽  
Face Centered ◽  
Fcc Phase ◽  
Film Form

Metastable face-centered cubic (fcc) solid solutions of Ni1–xAlx and Ni1–xZrx have been prepared in thin-film form using dc planar magnetron sputtering in a UHV system. In both these alloy systems, extended solubilities in the fcc phase and a pronounced (111) texture are observed after sputter deposition. An amorphous phase is found to form in Ni1–xAlx for x ≥ 0.30 and in Ni1–xZrx for x ≥ 0.05. Lattice constants, thermal expansion coefficients, and Debye temperatures were derived from x-ray diffraction measurements. These parameters were also calculated by using ab initio methods in the framework of the local-spin density and coherent potential approximations for the electronic subsystem and the Debye–Grüneisen model for the vibrational properties of the nuclei subsystem. Experiment and theory are compared and discussed.

Dielectric and thermal properties, expansion, and high-temperature plastic deformation of Cd4Na(VO4)3

1983 ◽  
Vol 16 (1) ◽  
pp. 133-135 ◽  
Author(s):  
S. C. Abrahams ◽  
K. Nassau ◽  
J. Ravez ◽  
A. Simon ◽  
R. Olazcuaga
Keyword(s):  
Phase Transition ◽  
Plastic Deformation ◽  
Second Harmonic ◽  
Linear Thermal Expansion ◽  
Optical Quality ◽  
Rapid Rise ◽  
Lattice Constants ◽  
Thermal Expansion Coefficients ◽  
Sensitivity Level ◽  
Expansion Coefficients

Cd4Na(VO4)3 has been reported as crystallizing in space group Pn21 a with all atoms displaced no more than 1/4 Å, from the corresponding positions in prototypic Pnma. Such an atomic arrangement is expected to be ferroelectric. Large optical-quality crystals, with no phase transition between 300 K and the melting point at 1165 K, have been grown. The piezoelectric d 22 coefficient is less than 0.1  pCN−1 and second-harmonic generation is undetectable at a sensitivity level capable of measuring a signal less than 0.001 that produced by quartz. The crystal is hence centrosymmetric at the 99% confidence level. The lattice constants at 294 K are a = 9.8189(3), b = 7.0298(2), c = 5.3610(1) Å, with linear thermal expansion coefficients of α(a) = 14.4, α(b) = 10.8, α(c) = 21.0 × 10−6 K −1 between 294 and 973 K. Plastic deformation sets in above 1060 K with an accompanying rapid rise both in dielectric permittivity and conductance.

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