Origin of Low-Frequency Noise in the Low Drain Current Range of Bottom-Gate Amorphous IGZO Thin-Film Transistors

The low-frequency noise of bottom-gate amorphous IGZO thin-film transistors is investigated in the low drain current range. The noise spectra show generation-recombination (g-r) noise at drain currents
I
_d
<; 5 nA, attributed to bulk traps located in a thin layer of the IGZO close to the conducting channel. At higher drain currents, a pure 1/
f
noise is observed. It is shown that the carrier number fluctuations are responsible for the 1/
f
noise due to trapping/detrapping of carriers in slow oxide traps, located near the interface with uniform spatial distribution.