Scanning tunneling microscopy analysis of ultrafast laser damage of single crystal silicon

Abstract

Laser processing is useful for topographical and band structure modification of semiconductors. We used a Scanning Tunneling Microscope (STM) to map topography of silicon (100) damaged with an ultrafast pulsed Yb:KGW laser at 1030 nm with duration of 70 fs in high vacuum. In particular we observed periodic surface structures ( λ 10 ≈ 100 nm spacing). dI/dV spectra can be combined with topography to understand the laser damage process better and eventually can be used to characterize defect formation without the presence of topographical change.

In-situ scanning tunneling microscopy of ultrafast laser damage on Si (100) surface in ultra-high vacuum

“…In particular, in situ characterization allows for atomic-scale imaging and spectroscopy by tools such as scanning tunneling microscopy (STM). 12 An in situ objective gives a tight focus (∼ 15µm) on the sample. A combination of in situ and ex situ laser machining is used to define a registration grid within the overlap region that can be accessed by the objective and the STM tip.…”