Fabrication of top-contact pentacene-based organic thin-film transistors with short channels using two-step SU8/poly(vinyl alcohol) lift-off photolithography process

Abstract

We propose a two-step SU8/poly(vinyl alcohol) (PVA) lift-off photolithography scheme for fabricating top-contact pentacene-based organic thin-film transistors (OTFTs) with small channels. The bilayer of PVA and SU8 will not damage the pentacene channel layer in the lift-off photolithography process used in forming the patterned pentacene channel layer and source/drain metal electrodes. We demonstrate a device that not only obtains a 5 µm short channel length for source/drain metal-electrode patterning but also avoids fringe current resulting from pentacene channel layer patterning. The field-effect mobility and threshold voltage of the pentacene-based OTFTs were changed from 0.29 to 0.12 cm2 V−1 s−1 and from −5.74 to −3.19 V by varying the channel length from 50 to 5 µm, respectively. The proposed scheme is a good candidate for use in the design and fabrication of high-performance short-channel organic electronics.

Organic doped diode rectifier based on parylene-electronic beam lithogrpahy process for radio frequency applications

“…The diode rectifier has been fabricated by "PPEBL" parylene patterning electron beam lithography with a process adapted for the first time for this kind of device. This process has been in part adapted from previous methods reported in the case of electrochromic displays [9][10][11][12][13]. As showed in (Fig.…”

“…By means of three layer lithographic process of polyvinyl alcohol (PVA) that serves as a protective layer for pentacene, Poly (metylmethacrylate) (PMMA) and ammonium dichromate (ADC), Kuo et al [8] have fabricated top contacts on a thin film layer of pentacene. Associating PVA and SU-8 photoresist, Fan et al [9] have created top contact pentacene based organic thin film transistor with patterning pentacene channel layer and source/drain metal electrodes. The lift-off process, was performed in deionized water following by baking in a vacuum oven to remove any residual water.…”

Solution‐Processed PTCDI‐C8 Crystalline Wire: Dual Role as Mask and Active Layer for Organic Transistors with Increased Switching Speeds

“…[23,24] Liftoff photolithography is a cost-effective alternative to the aforementioned techniques; however, it is complex and involves numerous steps. [25][26][27] Although non-lithographic methods such as Si etching and direct writing have also been developed, they have limitations. Si etching is cost-effective but only applicable to Si substrates.…”