La-doped ZrO2 thin films were grown by O3-based atomic layer deposition on III-V (GaAs,In0.15Ga0.85As) substrates through direct growth and after intercalation of a Ge interface passivation layer. The interface composition was investigated by x-ray photoelectron spectroscopy, revealing a dramatic reduction of semiconductor-oxygen bonding upon Ge passivation. An improved electrical quality of the Ge-passivated interfaces due to the removal of Ga3+ bonding related traps is demonstrated by conductance measurements at various temperatures.