[9p-Z18-1~21] 3.7 Laser processing

△ [9p-Z18-4] Discussion for formation mechanisms of periodic surface structures on semiconductors irradiated by mid-infrared free electron laser

〇Yohei Tanaka¹, Chikai Hosokawa¹, Masaki Hashida^1,2, Heishun Zen³, Takeshi Nagashima⁴, Norimasa Ozaki⁵, Shunsuke Inoue^1,2, Shuji Sakabe^1,2 (1.GSS, Kyoto Univ., 2.ICR, Kyoto Univ., 3.IAE, Kyoto Univ., 4.Setsunan Univ., 5.GSE, Osaka Univ.)

Keywords:Laser Induced Periodic Surface Structures, mid-infrared free electron laser, semiconductor

We have reported that the irradiation of long-wavelength and high-intensity mid-infrared free electron laser (MIR-FEL) on semiconductors can form fine periodic surface structures (LIPSS) with periodic interspaces large enough to be observed by visible lasers. This time, we have analyzed the formation threshold fluences and periodic interspaces of the LIPSS formed by MIR-FEL in detail and compared them with those of LIPSS formed by visible or near-infrared laser irradiation, and estimated necessary time resolution to observe the LIPSS formation process.