The composite thin film of WO3/silicon nanoporous pillar array（Si-NPA）is prepared and its surface morphology is characterized.The capacitive humidity sensing properties and the capacitance temperature drift of WO3/Si-NPA are studied.It is shown that WO3/Si-NPA inherites the regular pillar array

the morphological characteristic of Si-NPA substrate

and a continuous WO3 thin film is formed to make WO3/Si-NPA a typical nanocomposite thin film.Measured at room temperature

the capacitance of WO3/Si-NPA decreases monotonically with the testing frequency

but a maximum sensitivity is achieved at the testing frequency of 1

00 Hz.When the relative humidity changes from 11 %RH to 95 %RH

a capacitance increment is over 16 000 % is achieved.This indicates that WO3/Si-NPA is very sensitive to humidity.Furthermore

the capacitance response of WO3/Si-NPA to humidity exhibits high linearity.The research on the capacitance-temperature dependence shows that the best operation temperature zone is 15

5

0 ℃.