LSAT Lanthanum-Strontium Aluminium Tantalate Crystal Substrates

Material Name: Lanthanum Aluminate  Strontium Aluminium Tantalate, Lanthanum-Strontium Aluminium Tantalate (LSAT)

About LSAT: LSAT has the perovskite crystal structure, and it is commonly used as a single crystal substrate for the growth of epitaxial thin films.LSAT's cubic structure and lattice parameter of 3.868 Å makes it compatible for the epitaxial growth of a wide range of perovskite oxide thin film with a relatively low strain.

Chemical Formula:

(LaAlO₃)_0.3(Sr₂TaAlO₆)_0.7 or (La_0.18Sr_0.82)(Al_0.59Ta_0.41)O₃

Main Material Properties of LSAT

• Crystal growth method: Chralski (CZ) method
• Crystal structure: Cubic
• Lattice parameter: a = 3.868 Å
• Purity: 99.9% (trace metal basis)
• Melt point: 1840 °C
• Density: 6.74 g/cm³
• Hardness: 6.5 Mohs
• Dielectric constant:  22
• Thermal expansion coefficient: 10 X 10^-6/°C
• Thermal conductivity: 5.1 W/(m.K)

Crystal Orientation: (100), (110), (111)

Available Size: 5 mm x 5 mm, 10 mm x 10 mm, 25.4 mm (1 inch). Special sizes and orientations are available upon request.

Thickness: 0.5 mm, 1.0 mm

Surface polishing: Single or double side polished, Epi-ready surface, roughness Ra < 0.5 nm (5 um x 5 um area)

Packaging: Packing in class 1000 clean room with class 100 grade plastic bag

Applications of LSAT: LSAT is primarily used as single crystal substrates or wafers with 0.5 mm thickness. These substrates and wafers are used as a substrate material for the epitaxial growth of oxide thin films and their heterostructures. Typical materials grown on LSAT substrates include strontium titanate (SrTiO₃), cuprate superconductors (such as YBCO), iron-based superconductors (iron-pnictides), rare-earth manganites, rare-earth nickelates and others. Compound semiconductors such as gallium nitride (GaN) can also be grown on LSAT.

LSAT is used as a popular substrate for the epitaxial growth of oxide thin films because of its high chemical and thermal stability, and very low electrical conductivity. The growth conditions for such epitaxial layers can cause many other crystal substrates to form high densities of defects that can alter their properties. One example is the tendency of strontium titanate to form oxygen vacancy defects under high temperatures in high vacuum. These defects result in considerable variations of its properties, including the increase of electrical conductivity and optical opacity. In contrast, LSAT is stable in both oxidizing and fairly reducing atmospheres at high temperatures, thus enabling a larger operating window for the processing and growth conditions.