Temperature and frequency dependent electrical characterization of HfO ₂ / In_xGa_1-xAs interfaces using capacitance-voltage and conductance methods

Electrical properties of metal-oxide-semiconductor capacitors using atomic layer deposited HfO₂ on n -type GaAs or In_xGa _1-xAs (x=0.53, 0.30, 0.15) epitaxial layers were investigated. Capacitance-voltage (CV) measurements indicated large temperature and frequency dispersion at positive gate bias in devices using n -type GaAs and low In content (x=0.30, 0.15) In_xGa_1-xAs layers, which is significantly reduced for devices using In_0.53 Ga_0.47 As. For In_0.53 Ga_0.47 As devices, the CV response at negative gate bias is most likely characteristic of an interface state response and may not be indicative of true inversion. The conductance technique on Pd/ HfO ₂ / In0.53 Ga0.47 As/InP shows reductions in interface state densities by In_0.5 Ga_0.47 As surface passivation and forming gas annealing (325 °C).