Phonon scattering in thin silica films below 1 K

• Published in: Journal of low temperature physics Vol. 113; no. 1-2; pp. 123 - 139
• Main Authors: VU, P. D, OLSON, J. R, POHL, R. O
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.10.1998
• Subjects: Computer simulation; Condensed matter: structure, mechanical and thermal properties; Dielectric materials; Electron beams; Evaporation; Exact sciences and technology; Lattice dynamics; Monte Carlo methods; Nonelectronic thermal conduction and heat-pulse propagation in solids; thermal waves; Phonons; Phonons in low-dimensional structures and small particles; Physics; Quantum tunneling of defects; Silicon; Substrates; Thermal conductivity of solids; Thin films; Transport properties of condensed matter (nonelectronic); Inorganic compounds; Phonon-phonon interactions; Mean free path; Dielectric materials; Tunnel effect; Phonons; Amorphous state; Experimental study; Silica; Defects; Thin films; Thermal boundary resistance; Monte Carlo methods; Silicon oxides; Thermal conductivity; Transport processes
• ISSN: 0022-2291; 1573-7357
• DOI: 10.1023/a:1022593123280

A method is described for studying thermal phonon scattering in thin films on dielectric substrates below a few Kelvin. It is used to study silica films on silicon substrates. Using Monte Carlo simulations with no free parameters, we find that thermally grown silica films 0.1 to 1.0 mu m thick scatter the phonons as strongly as bulk silica, and hence, have the same thermal conductivity as bulk silica, while a 0.1 mu m thick e-beam evaporated silica film has a thermal conductivity five times smaller than bulk silica, indicative of additional defects.