Low-Frequency ( 1 ∕ f ) Noise Performance of n- and p-MOSFETs with Poly- Si ∕ Hf -Based Gate Dielectrics

Abstract

The low-frequency (LF) noise performance of n- and p-channel metal-oxide-semiconductor field-effect transistors (MOSFETs) with different Hf-based gate oxides, deposited by metallorganic chemical vapor deposition (MOCVD) on the same interfacial oxide layer and using polysilicon (poly-Si) as a gate material has been investigated. Independent of the gate oxide, the LF noise spectra of n- and p-MOSFETs are predominantly of the type, with the frequency exponent γ close to 1. For nMOSFETs, the noise spectral density of devices is two orders of magnitude higher than for or (silicates), where , most likely due to trapping by defects in the high- layer. For the silicates with different , no significant differences are noticed for n- and p-MOSFETs. It is shown that the noise characteristics behave as can be expected for a number fluctuations mechanism. The extracted volume and surface trap densities are significantly higher for pure than for the devices. In the latter case, trap densities comparable with the values for the reference transistors are obtained. Hooge’s parameter , as an alternative figure of merit, shows that the devices with MOCVD gate dielectric have the noisiest performance, while MOSFETs yield the lowest , even better than for .