Atomic Layer Deposition of Nanostructured Tunable Resistance Coatings: Growth, Characterization, and Electrical Properties

We have developed atomic layer deposition (ALD) methods to synthesize robust nanostructured composite coatings with tunable resistance comprised of conducting, metallic nanoparticles embedded in an amorphous dielectric matrix. These films are nominally composed of M:Al2O3 where M= W or Mo, and are prepared using alternating exposures to trimethyl aluminum (TMA) and H2O for Al2O3 ALD and alternating MF6/Si2H6 exposures for the metal ALD. By varying the ratio of ALD cycles for the metal and Al2O3 components in the film, we can precisely adjust the resistivity of these composite coatings over a very broad range (e.g. 10-10 Ohm-cm). Furthermore, the self-limiting nature of ALD allows us to grow these nanocomposite films on a variety of complex substrates such as high aspect ratio porous 3D surfaces, MEMS devices, ceramics, grid structures and microchannel plates. Here we present a detailed ALD study of the nanostructured composite resistance coatings including in-situ material growth, microstructural characterization, and electrical measurements.