Monolithic integration of high-voltage thin-film electronics on low-voltage integrated circuits using a solution process

The performance of silicon complementary metal–oxide–semiconductor integrated circuits can be enhanced through the monolithic three-dimensional integration of additional device layers. For example, silicon integrated circuits operate at low voltages (around 1 V) and high-voltage handling capabilities could be provided by monolithically integrating thin-film transistors. Here we show that high-voltage amorphous oxide semiconductor thin-film transistors can be integrated on top of a silicon integrated circuit containing 100-nm-node fin field-effect transistors using an in-air solution process. To solve the problem of voltage mismatch between these two device layers, we use a top Schottky, bottom ohmic contact structure to reduce the amorphous oxide semiconductor circuit switching voltage. These contacts are used to form Schottky-gated thin-film transistors and vertical thin-film diodes with excellent switching performance. As a result, we can create high-voltage amorphous oxide semiconductor circuits with switching voltages less than 1.2 V that can be directly integrated with silicon integrated circuits.