Maskless metal patterning by meniscus-confined electrochemical etching and its application in organic field-effect transistors

Abstract Conductive micropatterns is an essential part for operation of electronic devices in both industrial and academic fields. Conventional mask-based photolithography and vacuum deposition are inadequate to meet the demands of convenience and simplicity due to their complicated operation, costly instrumentations and relatively low resolution (for vacuum deposition). Development of simple and efficient mask-less fabrication techniques of conductive micropatterns is highly expected. Here we report a facile meniscus-confined electrochemical etching (MCEE) approach to fabricate metal micropatterns with resolution down to at least 1.0 μm. Both the applied bias and the moving velocity directly influence the patterning resolution. MCEE process is developed to fabricate source and drain electrodes in organic transistors on both rigid and flexible substrates. Being a maskless direct writing method, the width and morphology of the etched channel can be easily modulated by the bias and the velocity. The organic transistor with top-contact configuration presents better electrical performance with device on/off ratio of 1.1 × 105 and maximum carrier mobility of 1.07 cm2V−1s−1, which implies that MCEE operation doesn't result in the degradation of the already deposited semiconducting film. This mask-less MCEE approach provides a potential complementary to conventional mask-based techniques for the fabrication of microscale metal patterns.