Thermal Performance of Cu Electroplated GaN/AlGaN High-Electron-Mobility Transistors with Various-Thickness Si Substrates

Thermal dissipation is an important issue for power devices. In this work, the impact of thermal effects on the performance of Cu electroplated GaN-based high-electron-mobility transistors (HEMTs) are considered. Electrical, thermometry and micro-Raman characterization techniques were used to correlate the effects of improved heat dissipation on device performance for GaN HEMTs with different thicknesses of Si substrate (50, 100, 150 μm), with and without an additional electroplated Cu layer. GaN HEMTs on electroplated Cu on Si (≤50 μm) demonstrate an enhanced on/off current ratio compared to bare Si substrate by a factor of ~400 (from 9.61 × 10⁵ to 4.03 × 10⁸). Of particular importance, surface temperature measurements reveal a much lower channel temperature for thinner HEMT devices with electroplated Cu samples compared to those without.