Optimization of the ZTO/GI interface of Bottom-gate Amorphous ZnSnO Thin-Film Transistor

Abstract

Since ZnSnO Thin-Film Transistors (a-ZTO TFTs) are sensitive to the ZTO/GI interface, the crude quality of interface causes a series of problems. So we creatively used three methods to optimize the ZTO/GI interface. First, N2O plasma treatment applied to the gate insulator availably increases mobility (μsat) and restrains the instability. Second, when the rf sputtering power of active layer was reduced only near the interface, SSsat significantly decreased, although μsat and stability is a little degraded. Thirdly, the increasement of rf sputtering oxygen content can obviously optimize SSsat, following with the acceptable deterioration of μsat. Combining the three effective ways mentioned aboved, the result shows that the fabricated TFTs has μsat of 4.5±0.5 cm2/V∙s, a SSsat of 0.5±0.05 V/decade, and acceptable electrical stress stability under both positive and negative biases.