Thin-Film Heterojunction FETs on Poly-Si Substrates for High-Stability Driving and Low-Power Amplification

Thin-film heterojunction field-effect transistor (HJFET) devices with hydrogenated amorphous Si gate and hydrogenated poly-Si source and drain regions are demonstrated on small-grain poly-Si substrates. The transistor fabrication process (excluding poly-Si preparation) temperature is below 200 °C. The HJFET devices enable lower operation voltages, steeper subthreshold characteristics, lower flicker noise, and higher stability than conventional poly-Si devices. A low-power HJFET amplifier suitable for capacitive reading of biological signals is also demonstrated.