Facile Four-Mask Processes for Organic Thin-Film Transistor Integration Structure With Metal Interconnect

To enable an organic thin film transistor (OTFT) technology for circuit integration, the passivation layer and subsequent interconnect metallization on top of the OTFT is vital. In this work, a modified SU8 formulation is developed for forming the passivation layer on top of the OTFT with small molecule organic semiconductor (OSC). Based on the single SU8 passivation layer, via holes for interconnect metallization are easily formed, and the whole integration structure can be completed with facile four-mask processes. The OTFTs exhibit high mobility (> 2 cm
²
/V · s), low leakage (<; 10
^-11
A over the whole gate voltage range from 20 V to -30 V) at short channel length (8 μm), excellent uniformity and stable electrical properties during operation and storage. The results well prove that the process of the modified SU8 solution for passivation is compatible with the small molecule OSC layer, and formation of the via connection is reliable.