Atomic Layer Deposition of Hafnium Dioxide on TiN and Self-Assembled Monolayer Molecular Film

Abstract

Hafnium dioxide thin films with thicknesses ranging from 20 to 100 Å have been grown in a viscous flow reactor using atomic layer deposition (ALD) with tetrakis(dimethylamido)hafnium(IV) and water as the reactants. ALD films are deposited successfully at on different molecular monolayers. X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy analyses show a continuous growth of the layer on the self-assembled monolayer molecules. Electrical properties characterized by current–voltage measurements suggest that three parameters play important roles in determining the physical structure of , namely, the precursor pulse time, the sample exposure time, and the time for purging out an unreacted precursor. ALD conditions for different substrates have been optimized so that excellent electrical properties can be obtained for films on molecules. Transmission electron microscopy of 30 and 60 Å ALD on TiN and molecular monolayers shows a continuous deposition of . This process enables the development of a class of molecular electronic devices, solid-state molecular memory devices.