Omni -Directional Transistors: Enabling Tensile -Force -Resilient Operation for Flexible Circuits and Systems

Thin-film transistors suffer from mechanical strain, which limits their performance in wearable systems. This paper proposes an IGZO-based omni-directional transistor (OT), whose force-insensitive axis can be aligned to the direction of the external force by dynamically adjusting the voltage on the top gates. As a result, the strain-induced variation on mobility and threshold voltage can be significantly attenuated. Based on the proposed OTs, a ring oscillator (RO) is designed and simulated by applying tensile force in different directions. The OT-based ring oscillator can achieve less than 1% frequency variation under a 0.4% induced strain, which is 12x lower compared with the conventional transistors.