Intrinsically Photopatternable High-k Polymer Dielectric for Flexible Electronics

Abstract

The development of flexible and stretchable devices is crucial for realizing future electronics. In particular, for dielectric layer, conventional inorganic materials are limited by their brittle nature, while organic materials suffer from a low dielectric constant. Here, a novel intrinsically photopatternable high-k Parylene-based thin film (Parylene-OH) is fabricated via a chemical vapor deposition process based on the Gorham method, which provides pin-hole free, conformal polymeric film on any type of surface. Parylene-OH can be photo-patterned by UV crosslinking without further lithography processes and dielectric constant of Parylene-OH increases from 6.05 to 7.53 after crosslinking, without degrading other parameters, making it comparable to conventional high-k dielectric, Al2O3. Flexible InGaZnO (IGZO) thin-film transistors (TFTs) with patterned dielectric layers can withstand higher strain owing to the localized pattern of each unit. A CMOS inverter integrated with n-type IGZO and p-type Te TFTs is successfully fabricated. Parylene-OH can be used in the future of state-of-the-art flexible electronic devices.