Record Combination of Power-Gain Cut-Off Frequency and Three-Terminal Breakdown Voltage for GaN-on-Silicon Devices

We report on an emerging GaN double heterostructure grown on silicon, which enables the simultaneous achievement of high breakdown voltage and high frequency performance. The use of an AlN barrier layer capped by an in situ SiN layer, and the introduction of an AlGaN back barrier layer in addition to standard field plates enabled the achievement of a remarkable three-terminal breakdown voltage $V_{\text{BK}}$ of over 100 V together with a power gain $f_{\text{max}}$ above 200 GHz for the first time on GaN devices grown on silicon substrates. This results in a record combination of $f_{\text{max}}V_{\text{BK}}$ of above 20 THz V, promising breakthrough performance for widespread millimeter-wave applications.