講演情報
[10p-E201-17]Thickness and Substrate Dependence of Near-Field Thermal Signal in Thin Films
〇(M2)Yongzhi Wang1, Kuan-Ting Lin2, Guokang Zhang2,3, Yusuke Kajihara1,2 (1.Univ.Tokyo Dept.PE, 2.Univ. Tokyo IIS, 3.Fudan Univ. Dept Phy)
キーワード：
Near-field optics、Ultra thin metal film、Thermally excited evanescent wave
Continuous scaling of semiconductor devices has reduced the dimensions of metallic interconnects to the nanometer scale. As the thickness and linewidth of Cu interconnects decrease, their electrical, thermal, and optical properties deviate from those of bulk materials due to size-dependent effects. Understanding the electromagnetic behavior of ultrathin Cu films is therefore important for future nanoelectronic devices. Thermally excited evanescent waves generated near material surfaces play an important role in near-field radiative heat transfer. Although the probe-scattering mechanism of these waves has been studied for thick metallic structures, it remains unclear in ultrathin metallic films. The objective of this study is to investigate the near-field scattering mechanism of thermally excited evanescent waves in ultrathin Cu films. Thermal near-field decay curves were measured using a passive scattering-type scanning near-field optical microscope (s-SNOM) operating at a wavelength of 14.1 ± 0.5 μm. Cu films with thicknesses of 5–20 nm were deposited on several substrates. By analyzing the decay characteristics of different film–substrate systems, we investigate the probe-scattering mechanism of thermally excited evanescent waves in ultrathin Cu films. Furthermore, theoretical calculations based on fluctuational electrodynamics were performed to identify the contribution of substrate-supported thermal electromagnetic modes and elucidate the underlying physical mechanisms.