Basic investigation of HfO2 based metal–insulator–metal diodes

Very fast frequency response of metal-insulator-metal (MIM) diodes extends into the terahertz regime making them attractive as key elements as alternative to photovoltaic solar energy harvesting and ultrahigh speed wireless communication systems. The tunnelling phenomena, which is crucial for achieving high performance in these devices is extremely sensitive to the nanoscale structural and chemical quality of interface regions. Modern chemical deposition techniques like Pulsed Injected Metal-Organic Chemical Vapour Deposition (PICVD), Atomic Layer Deposition (ALD) and Atomic Vapour Deposition (AVD®) will be used for the extremely precise growth of thin HfO2 films on TiN bottom electrodes. However, different deposition techniques may give unpredictably different results in terms of film density, surface and interface property and consequently in physical properties of the device.In this work, the influence of deposition techniques on the charge transport characteristics of HfO2 MIM diodes was investigated by Conducting Atomic Force Microscopy (C-AFM) and X-ray Photoelectron Spectroscopy (XPS).