Heterogeneous integration of microscale gallium nitride transistors by micro-transfer-printing

Discrete gallium nitride high electron mobility transistors (HEMTs) are fabricated on <111> oriented silicon, then undercut and assembled onto non-native silicon CMOS wafers by elastomer stamp micro-transfer-printing. The thin, less than 5 um thick, gallium nitride transistors were then electrically interconnected using conventional thin-film metallization processes. Electrical measurements reveal that the heterogeneous integration process is benign to the underlying silicon transistors, and that the heterogeneous wide bandgap GaN transistors maintain their characteristic high voltage performance after being undercut and transferred to the nonnative CMOS wafer.