Patent attributes
A composite substrate configured for epitaxial growth of a semiconductor layer thereon is provided. The composite substrate includes multiple substrate layers formed of different materials having different thermal expansion coefficients. The thermal expansion coefficient of the material of the semiconductor layer can be between the thermal coefficients of the substrate layer materials. The composite substrate can have a composite thermal expansion coefficient configured to reduce an amount of tensile stress within the semiconductor layer at room temperature and/or an operating temperature for a device fabricated using the heterostructure.