Flexible thin-film transistors on planarized parylene substrate with recessed individual backgates

• A recessed-gate concept proposed on polymer substrates for planarization.
• A novel process was used to achieve evenly recessed-gates on flexible parylene.
• Substrate surface characterized and tested using a brittle thin film.
• In–Ga–Zn–O based thin film transistors fabricated on substrates.

With novel design and fabrication techniques, InGaZnO-based thin-film transistors with individual recessed back-gates were fabricated on flexible and transparent polymer substrates. The key components for the fabrication include using a machine park optimized for Si process technology, low-adhesion, room temperature parylene coating, AlOx–ZnOx(Al)-based inorganic lift-off process, and a recessed individual gate concept. Transistors were built to validate the viability of the design as well as aforementioned techniques. The demonstrated approach could open up new design possibilities for cheap, flexible devices, while the recessed-gate concept shows promise towards the use of more brittle layers in our flexible thin-film electronic devices.

The process flow of IGZO-based flexible recessed-gate transistors.Figure optionsDownload as PowerPoint slide