Accession Number : ADA506124


Title :   Alternative Dielectric Films for rf MEMS Capacitive Switches Deposited using Atomic Layer Deposited Al2O3/ZnO Alloys


Descriptive Note : Journal article


Corporate Author : COLORADO UNIV AT BOULDER DEPT OF MECHANICAL ENGINEERING


Personal Author(s) : Herrman, Cari F ; DelRio, Frank W ; Miller, David C ; George, Steven M ; Bright, Victor M ; Ebel, Jack L ; Strawser, Richard E ; Cortez, Rebecca ; Leedy, Kevin D


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a506124.pdf


Report Date : 02 Jul 2006


Pagination or Media Count : 12


Abstract : Atomic layer deposition (ALD) was used to deposit an alternative dielectric barrier layer for use in radio frequency microelectromechanical systems (rf MEMS). The layer is an alloy mixture of Al2O3 and ZnO and is proposed for use as charge dissipative layers in which the dielectric constant is significant enough to provide a large down-state capacitance while the resistivity is sufficiently low to promote the dissipation of trapped charges. This paper investigates Al2O3/ZnO ALD alloys deposited at 100 and 177 C and compares their material properties. Auger electron spectroscopy was used to determine the Zn concentrations in the alloy films, which was lower than expected. Atomic force microscopy images revealed an average surface roughness of 0.27 nm that was independent of deposition temperature and film composition. The dielectric constants of the Al2O3/ZnO ALD alloys films were calculated to be similar to pure Al2O3 ALD, being -7. Indentation was used to ascertain the modulus and hardness of the ALD films. Both the modulus and hardness were found to increase for the greater deposition temperature. ALD-coated rf MEMS switches showed a low insertion loss, -0.35 dB, and a high isolation, 55 dB at 14 GHz. Mechanical actuation of the ALD-coated devices showed lifetimes of over 1 billion cycles.


Descriptors :   *ALUMINUM OXIDES , *ATOMIC LAYER EPITAXY , *ZINC ALLOYS , *ZINC OXIDES , *MICROELECTROMECHANICAL SYSTEMS , *DIELECTRIC FILMS , *ALUMINUM ALLOYS , AUGER ELECTRON SPECTROSCOPY , DIELECTRIC PROPERTIES , MICROSCOPY , INSERTION LOSS , TRAPPING(CHARGED PARTICLES) , RADIOFREQUENCY , MECHANICAL PROPERTIES , REPRINTS


Subject Categories : Inorganic Chemistry
      Properties of Metals and Alloys
      Crystallography


Distribution Statement : APPROVED FOR PUBLIC RELEASE