Si\SiO2 double-barrier structures with ultrathin nanoscale layers were developed by using α-Si:H thin film depositions and subsequently plasma enhanced oxidation. The experimental equipment with source of wide aperture and high-density inductively coupled RF plasma (ICP) was used. The electrical properties of the manufactured MOS-structures were investigated through measurement of C-V and I-V characteristics. In the experiments we observed the charge effects related to the process of carrier transport through thin dielectric. Furthermore, the areas of differential negative resistance in I-V characteristics were detected. These structures can be used as resonant tunneling diodes.