Memory effects related to deep levels in metal–oxide–semiconductor structure with nanocrystalline Si

Abstract

Nanocrystalline (nc) -Si was grown on SiO2 by rapid thermal chemical vapor deposition. The tunneling oxide layer of a thickness of 4 nm was formed on p-type Si(100) by rapid thermal oxidation at 1050 °C for 30 s. Metal–oxide–semiconductor (MOS) structures were fabricated and capacitance–voltage characterization was carried out to study the memory effects of the nc-Si embedded in the MOS structure. We found the memory effect to be dominantly related to hydrogen-related traps, in addition to being influenced by the three-dimensional quantum confinement and Coulomb charge effects. Deep level transient spectroscopy reveal that the activation energies of the hydrogen-related traps are Ev+0.29 eV (H1) and Ev+0.42 eV (H2), and the capture cross sections are 4.70×10−16 cm2 and 1.44×10−15 cm2, respectively. The presence of Si–H and Si–H2 bonds was confirmed by Fourier transform infrared spectroscopy.