Impact of Substrate Termination on Dynamic On-State Characteristics of a Normally-off Monolithically Integrated Bidirectional GaN HEMT

The dynamic on-state resistance of monolithically integrated bidirectional GaN HEMTs assuming hard-switching in half-bridge topology is studied for different approaches of substrate termination. Passive substrate termination to one source node of the bidirectional GaN HEMT leads to asymmetrical on-state characteristics while a floating substrate results in symmetrical but noticeable R
_on
-increase. Resistive substrate termination is investigated to evaluate the prospective benefits and requirements of active substrate termination. The effective on-state resistance of the bidirectional GaN HEMT can be minimized by employing an optimized substrate termination resistance.