Effect of substrate–film lattice mismatch in La[sub 0.7]Ba[sub 0.3]MnO[sub 3−δ] thin films for transport properties

YSi2-x thin films were grown by depositing the yttrium metal thin films on (111)Si substrate followed by a rapid thermal annealing (RTA) at 450 to 1100°C. The x value of the YSi2-x films ranges from 0 to 0.3. The (0001) plane of the YSi2-x films have an ideal zero lattice mismatch relative to (111)Si surface lattice. The YSi2 has the hexagonal AlB2 crystal structure. The orientation relationship with Si was determined from the diffraction pattern shown in figure 1(a) to be and . The diffraction pattern in figure 1(a) was taken from a specimen annealed at 500°C for 15 second. As the annealing temperature was increased to 600°C, superlattice diffraction spots appear at position as seen in figure 1(b) which may be due to vacancy ordering in the YSi2-x films. The ordered vacancies in YSi2-x form a mesh in Si plane suggested by a LEED experiment.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010010490x ◽

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.

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Stoichiometry control and electronic and transport properties of pyrochlore Bi2Ir2O7 thin films

Physical Review Materials ◽

10.1103/physrevmaterials.2.114206 ◽

2018 ◽

Vol 2 (11) ◽

Cited By ~ 5

Author(s):

W. C. Yang ◽

Y. T. Xie ◽

X. Sun ◽

X. H. Zhang ◽

K. Park ◽

...

Keyword(s):

Thin Films ◽

Transport Properties ◽

Stoichiometry Control

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Fabrication, micro-structure characteristics and transport properties of co-evaporated thin films of Bi2Te3 on AlN coated stainless steel foils

Scientific Reports ◽

10.1038/s41598-021-83476-7 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Aziz Ahmed ◽

Seungwoo Han

Keyword(s):

Thin Film ◽

Crystal Structure ◽

Thin Films ◽

Stainless Steel ◽

Substrate Temperature ◽

Transport Properties ◽

Structural Defects ◽

Film Composition ◽

High Substrate ◽

Foil Substrate

AbstractN-type bismuth telluride (Bi2Te3) thin films were prepared on an aluminum nitride (AlN)-coated stainless steel foil substrate to obtain optimal thermoelectric performance. The thermal co-evaporation method was adopted so that we could vary the thin film composition, enabling us to investigate the relationship between the film composition, microstructure, crystal preferred orientation and thermoelectric properties. The influence of the substrate temperature was also investigated by synthesizing two sets of thin film samples; in one set the substrate was kept at room temperature (RT) while in the other set the substrate was maintained at a high temperature, of 300 °C, during deposition. The samples deposited at RT were amorphous in the as-deposited state and therefore were annealed at 280 °C to promote crystallization and phase development. The electrical resistivity and Seebeck coefficient were measured and the results were interpreted. Both the transport properties and crystal structure were observed to be strongly affected by non-stoichiometry and the choice of substrate temperature. We observed columnar microstructures with hexagonal grains and a multi-oriented crystal structure for the thin films deposited at high substrate temperatures, whereas highly (00 l) textured thin films with columns consisting of in-plane layers were fabricated from the stoichiometric annealed thin film samples originally synthesized at RT. Special emphasis was placed on examining the nature of tellurium (Te) atom based structural defects and their influence on thin film properties. We report maximum power factor (PF) of 1.35 mW/m K2 for near-stoichiometric film deposited at high substrate temperature, which was the highest among all studied cases.

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