Accession Number : ADA247848


Title :   Mechanics of Thin Films


Descriptive Note : Final rept. 1 Jul 1987-30 Jun 1991


Corporate Author : ROCHESTER UNIV NY DEPT OF MECHANICAL ENGINEERING


Personal Author(s) : Lambropoulos, John C


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a247848.pdf


Report Date : 06 Feb 1992


Pagination or Media Count : 144


Abstract : Problems in the mechanics and thermomechanics of thin films have been addressed. Anisotropic stresses in films of cubic anisotropy oriented along the 100, 111, or 110 normals on a substrate; Relaxation in thin films by time- independent plastic deformation along the film substrate interface, by cracking, or by stress-induced diffusional flow during film growth. The toughening effect on brittle components of thin films in residual compression has been calculated and compared to experimental data. Motivated by measurements (using the thermal comparator technique) of thin film thermal conductivity where the film conductivity was found to be up to two orders of magnitude lower than that of the corresponding solid, the thermal conductivity of thin dielectric films has been correlated to microstructural features such as grain size and film thickness. The implications of reduced film thermal conductivity were examined for laser damage where nonlinear effects were shown to be important. The effects of film anisotropy and interfacial thermal resistance have been analyzed and the contribution of microporosity to interfacial thermal resistance has been calculated. For thermally anisotropic films an equivalent isotropic film of properly chosen thickness and conductivity could be identified. Length scales have been established against which the film thickness is to be compared.


Descriptors :   *THIN FILMS , COMPRESSION , STRESSES , THERMOMECHANICS , THICKNESS , EXPERIMENTAL DATA , FILMS , SUBSTRATES , POROSITY , ISOTROPISM , ANISOTROPY , LENGTH , SCALE , RESIDUALS , NONLINEAR SYSTEMS , BRITTLENESS , MECHANICS , REDUCTION , THERMAL RESISTANCE , LASER DAMAGE , HEAT , THERMAL CONDUCTIVITY , DIELECTRIC FILMS , GRAIN SIZE , MICROSTRUCTURE , CONDUCTIVITY , INTERFACES , GROWTH(GENERAL) , CRACKS


Subject Categories : Electrical and Electronic Equipment


Distribution Statement : APPROVED FOR PUBLIC RELEASE