Charge trapping layer enabled high-performance E-mode GaN HEMTs and monolithic integration GaN inverters

In this work, high threshold voltage and breakdown voltage E-mode GaN HEMTs using an Al:HfOx-based charge trapping layer (CTL) are presented. The developed GaN HEMTs exhibit a wide threshold modulation range of Delta V-TH similar to 17.8 V, which enables the achievement of enhancement-mode (E-mode) operation after initialization process owing to the high charge storage capacity of the Al:HfOx layer. The E-mode GaN HEMTs exhibit a high positive V-TH of 8.4 V, a high I-DS,I-max of 466 mA/mm, a low R-ON of 10.49 Omega mm, and a high on/off ratio of similar to 10(9). Moreover, the off-state breakdown voltage reaches up to 1100 V, which is primarily attributed to in situ O-3 pretreatment effectively suppressing and blocking leakage current. Furthermore, thanks to the V-TH of GaN HEMTs being tunable by initialization voltage using the proposed CTL scheme, we prove that the direct-coupled FET logic-integrated GaN inverters can operate under a variety of conditions (beta = 10-40 and V-DD = 3-15 V) with commendable output swing and noise margins. These results present a promising approach toward realizing the monolithic integration of GaN devices for power IC applications.