Ultrafast Surface Reaction and Desorption Probed by Femtosecond Second Harmonic Generation: Cl Etching of Si(111) Surface

Abstract

In order to establish a new maicrofabrication of semiconductors, we need to clarify the mechanisms of reaction between material surfaces and reactive species. Especially, the dry etching process on Si surface is the most spreading process in the electronics applications and has been extensively studied [1]. The optical second harmonic generation is also a powerful technique to study surface science because of its surface sensitivity, non-detrimental and in-situ observation, and the ultrafast response [2]. Femtosecond time-resolved studies of the desorption and/or reaction on the metal or semiconductor surfaces have been carried out [3,4]. In this letter we report the results of the laser-induced surface reaction and/or desorption on the Si(111)/Cl₂ system by using the femtosecond second harmonic generation.