Temperature-Dependent Low-Frequency Noise Analysis of ZnO Nanowire Field-Effect Transistors

Low-frequency noise characteristics of ZnO nanowire field-effect transistors (FETs) are presented at temperatures down to 10 K. The carrier number fluctuation (CNF) model and Hooge's model are used to analyze the low-frequency noise in the studied devices. From 293 down to 200 K, the normalized noise power spectrum density (PSD) is proportional to (g
_m
/I
_d
)
²
due to CNF caused by the trapping and detrapping process between the channel carriers and oxide traps near the semiconductor and the dielectrics interface. In this case, the low-frequency noise is induced by flat-band voltage fluctuation. The density of the traps in the gate dielectrics near the Fermi level ranges from 9.4 × 10
¹⁰
to 3.8 × 10
¹⁰
cm
^-2
eV
^-1
from 293 and 200 K. At lower temperatures, from 150 down to 100 K, the noise mechanism is mobility fluctuation, attributed to electron and space-charge scattering due to the hoping process and slow motions of electrons. The extracted Hooge's parameter in this temperature ranges in the order of $10
^-3
to 10
^-2
. In the temperature range from 30 down to 10 K, the low-frequency noise is dominated by both CNF and mobility fluctuation caused by Coulomb scattering between oxide traps and electrons.