Large-Area Photonic Lift-off Process for Flexible Thin-Film Transistors

TL;DR

This paper introduces a rapid large-area photonic lift-off process that enables the efficient separation of flexible thin films from rigid glass carriers, facilitating high-throughput manufacturing of flexible electronics without damaging the devices.

Contribution

The authors develop a novel photonic lift-off method using broadband flashlamp pulses, demonstrating its effectiveness in producing flexible thin-film transistors with preserved performance.

Findings

The PLO process achieves rapid separation in 150 microseconds.

Flexible TFTs retain mobility after lift-off and bending.

Finite element modeling shows controlled temperature at the polymer interface.

Abstract

Fabricating high-performance and/or high-density flexible electronics on plastic substrates is often limited by the poor dimensional stability of polymer substrates. This can be mitigated by using glass carriers during fabrication, but removing the plastic substrate from a large-area carrier without damaging the electronics remains challenging. Here we present a large-area photonic lift-off (PLO) process to rapidly separate polymer films from rigid carriers. PLO uses a 150 microsecond pulse of broadband light from flashlamps to lift off functional thin films from a glass carrier substrate coated with a light-absorber layer (LAL). A 3D finite element model indicates that the polymer/LAL interface reaches 865 degrees C during PLO, but the top surface of the PI reaches only 118 degrees C. To demonstrate the feasibility of this process in the production of flexible electronics, an array of indium zinc oxide (IZO) thin-film transistors (TFTs) was fabricated on a polyimide substrate and then photonically lifted off from the glass carrier. The TFT mobility was 3.15 cm2V-1s-1 before and after PLO, indicating no significant change during PLO. The flexible TFTs were mechanically robust, with no reduction in mobility while bent. The PLO process can offer unmatched high-throughput solutions in large-area flexible electronics production.