Current conduction processes in high-κ Gd_(0.31)Ga_(0.1)O_(0.59)/Ga_(2)O_(3) gate dielectric stacks on GaAs

摘要

Current conduction processes in high-κ (κ=20.2) Gd_(0.31)Ga_(0.1)O_(0.59)/Ga_(2)O_(3) dielectric stacks grown on n-type GaAs by molecular beam epitaxy have been investigated. Metal-oxide-semiconductor capacitors have been characterized by current density (j) versus electric field (E) measurements at temperatures ranging from 90 to 450 K. For temperatures T≤200 K, the high field (4.5≤E≤6.2 MV/cm) current is temperature independent and a Fowler-Nordheim tunneling slope of 1.75 eV~(3/2) is obtained. Frenkel-Poole emission is found to dominate at temperatures of 300 K and above at moderate electric fields (1.3≤E≤2.2 MV/cm). For Frenkel-Poole emission, a barrier height of 1.1 eV and a dynamic dielectric constant of 7.95 is derived from ln(j/E) vs 1/T and ln(j/E) vs E~(1/2) plots, respectively.