Self-aligned double injection-function contact mitigating short channel effects in sub-micron channels of solution processed indium gallium zinc oxide

Abstract

We propose and demonstrate self-aligned Double Injection Function Thin Film Transistor (DIF-TFT) architecture that mitigates short channel effects in 200nm channel on a non-scaled insulator (100nm SiO2). In this conceptual design, a combination of an ohmic-like injection contact and a high injection-barrier metal allows maintaining the high ON currents while suppressing the drain-induced barrier lowering. Using an industrial 2D device simulator (Sentaurus), we propose two methods to realize the DIF concept and we use one of them to experimentally demonstrate a DIF-TFT based on solution processed IGZO. Using molybdenum as the ohmic contact and platinum as the high injection barrier, we compare three transistor’s source-contacts: ohmic, Schottky, and double injection function. The fabricated DIF-TFT exhibits saturation at sub 1V drain bias with only about a factor of 2 loss in ON current compared to the ohmic contact.