Abstract: High quality epitaxial layers of monocrystalline materials can be grown overlying monocrystalline substrates such as SiC or sapphire by forming a compliant substrate for the growing the monocrystalline layers. Devices and methods for fabricating silicon carbide based heterojunction bipolar devices such as transistors and diodes. These devices are suitable for high power and/or high speed and/or high temperature electronic applications.