1/f noise as function of thickness in Al-doped ZnO thin films

AZO thin films were prepared on glass substrate by RF sputtering at room temperature. The sheet resistance, R
sh
[Ω] the resistivity, ρ[Ω.cm] and the 1/f noise were studied as a function of thickness, t from 50 nm to 450 nm. The 1/f noise normalized for bias, frequency and unit area, C
us
is proportional with the sheet resistance R
sh
. Our results show that the resistivity decreases with thickness. The ratio K = C
us
/R
sh
is proportional to t
²
, which indicates that mobility and the noise parameter α
H
shrink with a shrinking thickness.