Low-damage patterning of pentacene using a SiN x /PVA-photoresistmulti-layermask

We have developed a photolithographic technique of patterning a pentacene layer with low damage using a SiN x /poly(vinyl alcohol) (PVA) photoresist multi-layer mask. We used a hexavalent chromium-free PVAphotoresist. By inserting a SiN x buffer layer between the pentacene layer and the PVAphotoresist layer, we could suppress an increase in off current caused by interaction between pentacene and the photosensitive functional group in the PVA photoresist. In the patterning process, we found that carriers generated by O 2 -plasma doped into the pentacene layer and the off current of the pentacene thin-film transistor (TFT) increased.We also found that successive annealing caused de-doping of the pentacene layer and reduced off current of the pentacene TFT.We investigated the density of doped carriers using a simplemodel of a planer pentacene diode aswell as a pentaceneTFT.