Chemical processes involved in the etching of silicon by xenon difluoride

Abstract

The spontaneous etching of silicon by xenon difluoride has been investigated under single collision conditions using multiphoton ionization mass spectrometry for the detection of radical products. SiF2 is the only gas phase radical observed with an apparent activation energy of 6.7±0.5 kcal/mol. Electron ionization techniques were used to determine an apparent activation energy for gas phase production of SiF4 of 5.6±0.8 kcal/mol. The identification of SiF2 as the sole reactive desorbing species during the steady-state etching process is useful for understanding many aspects of primary surface processes and secondary gas phase reactions in etching.