Improved dielectric properties of BeO thin films grown by plasma enhanced atomic layer deposition

Abstract

Beryllium oxide (BeO) thin films were grown on a p-type Si substrate by plasma enhanced atomic layer deposition (PEALD) using diethylberyllium as a precursor and O2 plasma. The PEALD BeO exhibited self-saturation and linear growth rates. The dielectric properties of PEALD were compared with those of thermal atomic layer deposition (ThALD). X-ray photoelectron spectroscopy was performed to determine the bandgap energy of PEALD BeO (8.0 eV) and ThALD BeO (7.9 eV). Capacitance–voltage curves revealed that PEALD BeO had low hysteresis and frequency dispersion compared to ThALD BeO. In addition, PEALD showed a dielectric constant of 7.15 (at 1 MHz) and low leakage current (7.25×10-9 A/cm2 at −1 MV/cm). These results indicate that the highly activated radicals from oxygen plasma prompt the chemical reaction at the substrate, thus reducing nucleation delay and interface trap density.