Electrical conduction mechanisms in plasma-enhanced chemical vapor deposited SiO2 dielectric films

Abstract

In this study, SiO2 films with thicknesses 50 nm were grown on n-GaAs substrate by plasma enhanced chemical vapor deposition technique. To investigate the electrical transport mechanisms, Au/SiO2/n-GaAs (MOS) type capacitor structures were fabricated and measured current density-voltage (J-V) characteristics at room temperature. As a function of the applied gate voltage, Schottky emission, Frenkel-Poole emission, and trap-assisted tunneling were found as dominant current transport mechanisms under depletion mode. The obtained trap levels were attributed to defects related with the Ga vacancies formed at the SiO2/GaAs interface.