No abstract

No abstract

The set of MOS structures formed on n-type Si substrate with (NAOS)-SiO 2 /HfO 2 gate dielectric layers was prepared and annealed in N 2 atmosphere at various temperatures to stabilize the structure and to decrease the interface states density. Two Acoustic DLTS techniques using both surface (SAW) and longitudinal (LAW) acoustic waves including acoustoelectric response signal versus gate voltage dependence (U ac -U g characteristics) were used to characterize the interface states and the role of annealing treatment. The main interface deep centers with activation energies about 0.30 and 0.20 eV, typical for dangling bonds were observed as well as a particular influence of annealing treatment on the interface states. The obtained results are analyzed, discussed and mutually compared.

New technique of acoustic spectroscopy to study interface states in metal-oxide-semiconductor (MOS) structures with a very thin oxide layer based on the acoustoelectric effect resulting from the interaction between the longitudinal acoustic wave and semiconductor-insulator interface is presented. The essential principles and theoretical background of this acoustic spectroscopy technique that can determine the interface states distribution from the measured acoustoelectric response signal as a function of gate voltage (Uac-Ug characteristics) are described. The results obtained on the representative set of MOS structures prepared on both n- and p-type Si substrates by nitric acid oxidation of Si technology and undergone also some thermal treatment demonstrate that the introduced technique of acoustic spectroscopy can be a very useful tool for the interface states characterization.