Researchers from universities in Surrey, Cambridge and Rome have demonstrated a new transistor structure that can reduce the complexity of display drivers in flexible electronics and wearables.
The source-gated transistor (SGT) creates a compact circuit blocks, replacing 12 gtraditional thin film transistors (TFT) in a display driver with just two devices.
The project built polysilicon common-source amplifiers that showed a gain of 49 dB gain, the highest reported for a two transistor unipolar circuit. Current mirrors fabricated in polysilicon and InGaZnO have, in addition to excellent current copying performance, the ability to control the temperature dependence (degrees of positive, neutral or negative) of output current solely by choice of relative transistor geometry.
SGT transistors can be used for local amplification of sensor output for improved signal integrity, as well as temperature-regulated delay stages and timing circuits for homeostatic operation in wearables. These design blocks will benefit sensor front-ends, temperature sensors, pixel drivers, bias analogue blocks and high-gain amplifiers, particularly in systems using flexible substrates and wearable designs.
"We are entering what may be another golden age of electronics, with the arrival of 5G and IoT enabled devices. However, the way we have manufactured many of our electronics has increasingly become overcomplicated and has hindered the performance of many devices,” said Dr Radu Sporea, lead author of the study and Lecturer in Semiconductor Devices at the University of Surrey.
"Our design offers a much simpler build process than regular thin-film transistors. Source-gated transistor circuits may also be cheaper to manufacture on a large scale because their simplicity means there is less waste in the form of rejected components. This elegant design of large area electronics could result in future phones, fitness tracker or smart sensors that are energy efficient, thinner and far more flexible than the ones we are able to produce today."
The SGT transistor approach has been under development for a decade for such systems: ROLL-UP DIGITAL SCREENS NEAR REALITY FOR