Thermal Modelling of Monolithic Half-bridge IC with Integrated Gate Drivers and Power e-HEMT Based on GaN-on-SOI Platform

The results of thermal simulation of a monolithic half-bridge GaN power IC with integrated gate drivers and e-mode HEMT, developed on IMEC GaN-on-SOI platform are presented in the paper. Based on the assessment results of average power dissipated in the functional blocks of a GaN half-bridge power IC operating as part of a buck synchronous DC-DC converter, it had been established that the main heat sources in the IC were the half-bridge GaN HEMTs. The heat from the half-bridge GaN HEMTs propagates in the die and leads to heating of the logic block and gate drivers. Heating of half-bridge GaN HEMTs leads to increased channel resistance and IC output current drop. Heating of the gate drivers reduces driving current, as a result, increases the switching time of the half-bridge GaN HEMTs. Heating of the logic block increases the rise and fall times of the generated control signals, which worsens the dynamic characteristics of the IC.