The low-frequency noise characteristics of HfO2-based dielectrics have been investigated. Attention is given to the deposition technique (metal oxide chemical vapor deposition or atomic layer deposition) used, the HfO2 film thickness, and the use of a SiO2 interface layer. n-Type metal oxide semiconductor devices with equivalent oxide thicknesses (EOTs) of 1.5, 2, 3, and 5.5 nm were studied. It is shown that the LF noise of such high-k transistors is 1/f like. The behavior of the normalized current spectral density vs the drain current points out that for relative thin interfacial layers and at high gate voltages carrier trapping in the HfO2 layer governs the current fluctuations. The trap densities extracted from the noise are up to 200 times higher than in a thermal oxide reference wafer (5.5 nm EOT). The deposition technique has no strong impact on the density of traps in the high-k layer, which is in the range of 2-20 x 10(19) cm(-3) eV(-1). However, a strong difference was observed in the 1/f noise contribution, which is dominated by carrier scattering at charged traps. For HfO2, the scattering coefficient derived from the 1/f noise is smaller than for SiO2, which can be interpreted in terms of the suppression of the coulomb scattering by the high dielectric constant. (c) 2005 The Electrochemical Society.