Monolithically patterned high mobility solution-processed metal-oxide TFTs with metallic capping layers

Abstract

Amorphous indium gallium zinc oxide(IGZO) based thin film transistors(TFTs) have been widely studied due to their good electrical properties such as optical transparent and field effect mobility. The demand for low-cost process of thin film devices has needed solution processed metal oxide TFTs. Although many effective ways of fabricating soluble metal oxide TFTs have been investigated1, there is still the necessity of increasing field effect mobility of TFTs. As a one way of mobility improvement, low work function metals(Ca, Ti) were used as passivation in terms of capping layer on top of the IGZO active layer2,3. The metal capping method has obvious several advantages, but we expect the additional process cost due to a step of patterning the capping layer. Also, because nature of metals has no transparent characteristics, this pure metal capping method could not available in transparent applications. In this paper, we suggest a real time deposition method of electrodes and capping layer for solution processed IGZO TFTs with maintaining transparency and process cost.