1. Flexible IGZO TFT Spice model and design of active strain-compensation circuits for bendable active matrix arrays
- Author
-
Niko Munzenrieder, Wan Fazlida Hanim Abdullah, Julio C. Costa, Wan Muhammad Hilmi bin Wan Zaidi, and Arash Pouryazdan
- Subjects
010302 applied physics ,Materials science ,business.industry ,Circuit design ,Transistor ,Spice ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Electronic, Optical and Magnetic Materials ,Threshold voltage ,law.invention ,Active matrix ,law ,Thin-film transistor ,0103 physical sciences ,Optoelectronics ,Electrical and Electronic Engineering ,Resistor ,0210 nano-technology ,business ,Electronic circuit - Abstract
The detailed measurement and characterization of strain-induced performance variations in flexible InGaZnO thin-film transistors (IGZO TFTs) resulted in a SPICE TFT model able to simulate tensile and compressive bending. This model was used to evaluate a new concept, namely, the active compensation of strain-induced performance variations in pixel driving circuits for bendable active matrix arrays. The designed circuits can compensate the mobility and threshold voltage shifts in IGZO TFTs induced by bending. In a single TFT, a drain current of 1mA varies by $83~\mu \text{A}$ per percent of mechanical strain. The most effective compensation circuit design, comprising one additional TFT and two resistors, reduces the driving current variation to $1.1~\mu \text{A}$ per percent of strain. The compensation circuit requires no additional control signals and increases the power consumption by only $235~\mu \text{W}$ (corresponds to 4.7%). Finally, switching operation is possible for frequencies up to 200 kHz. This opens a way toward the fabrication of flexible displays with constant brightness even when bent.
- Published
- 2018