A method for forming a resistive random access memory (RRAM) device is disclosed. The method comprises forming a first electrode, forming a resistive switching oxide layer comprising a metal oxide by thermal atomic layer deposition (ALD) and forming a second electrode by thermal atomic layer deposition (ALD), where the resistive switching layer is interposed between the first electrode and the second electrode. Forming the resistive switching oxide may be performed without exposing a surface of the switching oxide layer to a surface-modifying plasma treatment after depositing the metal oxide.