Holistic optimization technique for solving low thermal conductivity of sapphire substrates in high frequency devices

The recent upsurge in wireless communications demands devices working at higher frequencies with higher output densities. In general, wide-bandgap materials seem to be the reliable choice for these applications, specifically GaN HEMT that has shown great advantage over its previous counterparts. A holistic optimization technique is proposed to define the stages that a high frequency, high power device is designed. An issue with the thermal conductivity of the substrates for these devices is also addressed and a fabrication technique is proposed to solve it.