Self-Aligned Double Injection-Function TFT for Deep Sub-Micrometer Channels' Length - Application to 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 200 nm channel on non-scaled insulator (100 nm SiO2). In this conceptual design, a combination of ohmic-like injection contact and a high injection-barrier metal allows maintaining the high ON currents while suppressing drain-induced barrier lowering (DIBL) effects. Using an industrial 2-D device simulator (Sentaurus), we propose two methods to realize the DIF concept. We use one of them to demonstrate, experimentally, a DIF-TFT based on solution-processed indium gallium zinc oxide (IGZO). Using molybdenum as the ohmic contact and platinum as the high injection barrier, we compare three transistors' source-contacts: ohmic, Schottky, and DIF. The fabricated DIF-TFT exhibits saturation at sub 1 V drain bias with only about a factor of 2 loss in ON current compared to the ohmic contact.