Department of Mechanical Engineering
Kenneth E. Goodson
Asheghi, M., Leung, Y.K., Wong, S.S., and Goodson, K.E., 1997, "Phonon-Boundary Scattering in Thin Silicon Layers," Applied Physics Letters, Vol. 71, pp. 1798-1800.
Temperature fields in microdevices made from silicon-on-insulator ~SOI! wafers are strongly influenced by the lateral thermal conductivity of the silicon overlayer, which is diminished by phonon scattering on the layer boundaries. This study measures the thermal conductivity of single-crystal silicon layers in SOI substrates at temperatures between 20 and 320 K using Joule heating and electrical-resistance thermometry in microfabricated structures. Data for layers of thickness between 0.4 and 1.6 mm demonstrate the large reduction resulting from phonon-boundary scattering, particularly at low temperatures, and are consistent with predictions based on the phonon Boltzmann transport equation.