[18p-E214-1~13] 22.1 Joint Session M "Phonon Engineering"

[18p-E214-7] Observation of large thermal conductivity reduction in thick Si phononic crystal membranes

〇Ryoto Yanagisawa¹, Masahiro Nomura¹ (1.IIS Univ. of Tokyo)

Keywords:nano structure, thermal phonon transport, silicon

We fabricated 670-nm-thick silicon membranes with phononic crystal nanostructures. We measured thermal conductivities of membranes by means of the thermoreflectance method. Compared with previous 145-nm-thick samples, the thick samples showed higher thermal conductivity depending on thickness. We observed, however, a large reduction of thermal conductivity in thick samples with phononic crystal nanostructures due to strong confinement of phonon in-plane direction.