Small low-frequency noise IGZO TFTs using a bilayer HfO2/SiO2 dielectric and the applications of IGZO TFTs to biosensors

The device exhibits a SS (subthreshold swing) of 95mV/decade, an on to off ratio over 10
⁹
, a hysteresis free transfer curve, and a high saturation current of 400µA when biased at V
GS
=2.5V and V
DS
=3V. Under these high performance, the device exhibits small low frequency noise. The corresponding Hooge's parameter can further reduce to 3.26×10
⁻⁴
. Series measurements including contact resistance, constant current stress, high low frequency CV were employed to reveal the origin of the small LFN.