Thermal conductivity evaluation of GaN–AlN–(4H)SiC hetero-epitaxial material system

In this work, the effective thermal conductivity of GaN–AlN–(4H)SiC hetero-epitaxial material system, is evaluated. The thermal conductivities of the bulk (substrate) Si, (4H)SiC, AlN, and GaN materials and the epitaxial-layers of the materials used in GaN–AlN–(4H)SiC hetero-epitaxial material system, are also evaluated using Callaway approach. It is observed that the GaN–AlN–(4H)SiC hetero-epitaxial material system has the effective thermal conductivity of approximately 2.0 W/cm K neglecting the (4H)SiC substrate and approximately 4.0 W/cm K, while considering the (4H)SiC substrate. Thus, this hetero-epitaxial material system is suitable to make semiconductor devices, not only for high-voltage, and high operation frequency, but also favorable for high temperature operation in comparison to the devices made up of discrete materials e.g., Si, (4H)SiC, and GaN.