Grant: Collaborative Research and Development Grants

Conventional approaches to large-area electronics fabrication relies on direct monolithic integration. While optimized for rigid high-melting point substrates, such as silicon or glass, these processes may not be the best approach for fabricating flexible electronics. In many cases, the ideal growth substrate for a specific thin-film heterostructure may not be the ideal substrate from the standpoint of heat extraction, mechanical properties, thermomechanical behavior, optical transparency, electrical conductivity or chemical compatibility. In these situations, it may be more advantageous to remove the growth substrate, although it is not always practical if the approach involves only mechanical or chemical means. Laser processing using absorbing thin films on transparent substrates has been shown to be effective in processing wide-bandgap devices for ultra-high output light-emitting diodes. Pulsed-laser processing provides the spatial capability of heating a controlled volume of material defined by the irradiation area and the thermal diffusion length of the solid. This spatial control allows for selective decomposition of thin-film structures that does not affect the surrounding material outside the heating zone. A selective liftoff process combined with wafer bonding processes will enable thin-film transistors on transparent substrates to be removed from the original growth substrate and integrated onto optimized platforms to enhance performance and functionality. The research proposed will enable commercialization of novel approaches for heterogeneous integration of metal oxide thin-film transistors to manufacture high-performance flexible electronics on plastic or cloth substrates. This approach would enable optimized devices processed on one platform followed by transfer and integration onto a separate platform, enhancing device functionality and performance of large-area flexible displays.