Tuning the Electrical Properties of Tungsten Oxide Thin Films Deposited by Reactive Magnetron Sputtering

Abstract

Tungsten oxide films are deposited onto glass and silicon substrates using reactive magnetron sputtering. Several studies have revealed difficulties in studying the electrical properties of resistive WOx films. The main objective of this work is to propose the capacitance meter as a method for studying the electrical properties of resistive WOx films. In addition, we aim to establish the correlation between the deposition process and WOx physico-chemical properties. The study of the W-Ar-O2 system hysteresis permitted us to gather the films into four zones, which were delimited by different oxygen flow rate intervals. The identification of these zones was confirmed by the deposition rate, target voltage, chemical composition and electrical properties of the films. A gradual evolution of the capacitance-voltage curves of the metal-oxide-semiconductor structures, with the WOx thin films as the oxide layer, was globally observed with increasing oxygen flow rate. Ion density (Nss) and flat band voltage (Vfb) evolved inversely to oxygen flow rate. The relationship between the evolution of Nss and Vfb and the increase in oxygen flow rate reflects the improvement in oxygen stoichiometry in the WOx films. The WOx-Si interface trap density distribution (Dit) was also studied using the Terman method. It was observed that the films closest to stoichiometry, i.e., WO2 or WO3, showed the lowest values of Dit and Nss.

Suppression of Oxide and Interface Charge Density in Radio Frequency Sputtered Ta2O5 Thin Films

“…But at 2:3 and 3:2 Ar/O 2 gas flow ratio the excess oxygen flow rate could generate O 2− ions, which pushes back the C – V curve toward negative bias. [ 51 ] Similarly, a minimum D it of 2.62 × 10 12 eV −1 cm −2 was found for 3:2 Ar/O 2 gas flow ratio. The effective dielectric constant of samples for Ar/O 2 flow ratio of 1:4–4:1 varies as 17.2, 15.6, 18, and 16, respectively.…”

Thermal Annealing Effect on the Structure, Optical and Electrical Properties of Lanthanum Manganite Thin Films Prepared by Reactive Co-Sputtering

“…After the value of C FB is known, the value of V FB can be deduced from the C-V curve data by interpolating between the closest V g values. More details on this technique can be found in a previous paper [23].…”