Growth properties and resistive switching effects of diamond-like carbon films deposited using a linear ion source

Abstract

Diamond-like carbon (DLC) films were prepared using an anode-layer linear ion beam source with C2H2 as the precursor and various negative bias voltages. The growth properties, microstructures, mechanical properties, and the resistive switching behaviors of the as-deposited DLC films were investigated as a function of bias voltage. The results showed that adjusting the bias voltage could vary the carbon atomic bonding structure (sp3/sp2 carbon hybridized bonding) of the films. The sp3/sp2 ratio initially increased as bias voltage increased and then decreased once the bias voltage exceeded −100 V. The variations in the film hardness and residual stress at different bias voltages were similar in profile to the sp3 bond fractions, indicating that both the residual stress and the mechanical properties of the DLC films were highly dependent on sp3-C bonding structures. The resistive switching characteristics of the DLC films were studied via a Cu/DLC/Pt cell structure. It was found that the bias voltages had a significant influence on the resistive switching behaviors of the DLC films. The film deposited with a bias voltage of 0 V showed excellent resistive switching effects with an ON/OFF ratio higher than 70 and device yield of about 90%, while the films deposited with higher bias voltages presented poor resistive switching effects. The sp2/sp3 ratio of the films was believed to account for the favorable resistive switching performances.