化工学报 ›› 2011, Vol. 62 ›› Issue (S1): 48-53.

• 流体力学与传递现象 • 上一篇    下一篇

多晶金薄膜电子-声子耦合的实验研究

马维刚,王海东,张兴,王玮   

  1. 清华大学工程力学系,热科学与动力工程教育部重点实验室,北京 100084;北京大学微电子学研究院,北京 100871
  • 出版日期:2011-07-03 发布日期:2011-07-03

  • Online:2011-07-03 Published:2011-07-03

摘要:

随着电子器件和高频雷达等的尺寸减小、工作频率提高及飞秒激光超快加工的广泛应用,金属中的电子-声子耦合都成为重要的影响因素。对于尺寸效应会不会增强多晶金属薄膜的电子-声子耦合仍然存在争议。本文采用飞秒激光背面泵浦-表面探测热反射方法,对不同厚度金薄膜中的电子-声子耦合过程进行了实验研究。研究结果表明薄膜中的电子-声子耦合和体材料基本相同,并且不随薄膜厚度及晶粒尺寸发生变化。通过对表面和晶界对电子-声子耦合的机理分析发现,在多晶薄膜中电子弛豫通过电子-声子、电子-晶界及电子-表面耦合实现,但是电子与晶界及表面的耦合作用远比和声子的耦合弱,因此多晶薄膜的电子-声子耦合过程和体材料相近,且不随薄膜厚度发生变化。

关键词: 电子FONT-SIZE: 10.5pt, mso-bidi-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-fareast-font-family: 宋体, mso-hansi-font-family: 宋体, mso-bidi-font-size: 11.0pt, mso-ascii-theme-font: minor-latin, mso-fareast-theme-font: minor-fareast" lang=EN-US>-FONT-SIZE: 10.5pt, mso-ascii-font-family: Calibri, mso-bidi-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-bidi-font-size: 11.0pt, mso-ascii-theme-font: minor-latin, mso-fareast-theme-font: minor-fareast">声子耦合;金薄膜;泵浦FONT-SIZE: 10.5pt, mso-bidi-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-fareast-font-family: 宋体, mso-hansi-font-family: 宋体, mso-bidi-font-size: 11.0pt, mso-ascii-theme-font: minor-latin, mso-fareast-theme-font: minor-fareast" lang=EN-US>-FONT-SIZE: 10.5pt, mso-ascii-font-family: Calibri, mso-bidi-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-bidi-font-size: 11.0pt, mso-ascii-theme-font: minor-latin, mso-fareast-theme-font: minor-fareast">探测热反射;飞秒激光

Abstract:

With the size reduction and operation frequency increase in electronic devices and high radio frequency radarand wide application of femotosecond laser ablationelectron-phonon coupling in metals plays a more and more important role.Howeverit is still an open question whether the electron-phonon coupling in polycrystalline thin metallic films will be affected by size effect.In this paperthe electron-phonon coupling in several gold films of different thickness has been studied by using rear-pump front-probe thermoreflectance technique.The measured electron-phonon coupling factors are nearly the same as that of bulk gold and independent of film thickness.It has been found that the electron energy relaxation in thin gold films occur through bulk electron-phononelectron-grain boundaryand electron-surface couplings.But the strength of electron-grain boundary and electron-surface coupling is sufficiently weak compared to the corresponding bulk electron-phonon interaction.

Key words: 电子FONT-SIZE: 10.5pt, mso-bidi-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-fareast-font-family: 宋体, mso-hansi-font-family: 宋体, mso-bidi-font-size: 11.0pt, mso-ascii-theme-font: minor-latin, mso-fareast-theme-font: minor-fareast" lang=EN-US>-FONT-SIZE: 10.5pt, mso-ascii-font-family: Calibri, mso-bidi-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-bidi-font-size: 11.0pt, mso-ascii-theme-font: minor-latin, mso-fareast-theme-font: minor-fareast">声子耦合;金薄膜;泵浦FONT-SIZE: 10.5pt, mso-bidi-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-fareast-font-family: 宋体, mso-hansi-font-family: 宋体, mso-bidi-font-size: 11.0pt, mso-ascii-theme-font: minor-latin, mso-fareast-theme-font: minor-fareast" lang=EN-US>-FONT-SIZE: 10.5pt, mso-ascii-font-family: Calibri, mso-bidi-font-family: 宋体, mso-ansi-language: EN-US, mso-fareast-language: ZH-CN, mso-bidi-language: AR-SA, mso-bidi-font-size: 11.0pt, mso-ascii-theme-font: minor-latin, mso-fareast-theme-font: minor-fareast">探测热反射;飞秒激光