Article

Applied Physics A

, Volume 114, Issue 4, pp 1009-1016

Improving dopant incorporation during femtosecond-laser doping of Si with a Se thin-film dopant precursor

  • Matthew J. SmithAffiliated withDepartment of Materials Science and Engineering, Massachusetts Institute of Technology Email author 
  • , Meng-Ju SherAffiliated withDepartment of Physics, Harvard University
  • , Benjamin FrantaAffiliated withSchool of Engineering and Applied Sciences, Harvard University
  • , Yu-Ting LinAffiliated withSchool of Engineering and Applied Sciences, Harvard University
  • , Eric MazurAffiliated withDepartment of Physics, Harvard UniversitySchool of Engineering and Applied Sciences, Harvard University
  • , Silvija GradečakAffiliated withDepartment of Materials Science and Engineering, Massachusetts Institute of Technology

Rent the article at a discount

Rent now

* Final gross prices may vary according to local VAT.

Get Access

Abstract

We study the dopant incorporation processes during thin-film fs-laser doping of Si and tailor the dopant distribution through optimization of the fs-laser irradiation conditions. Scanning electron microscopy, transmission electron microscopy, and profilometry are used to study the interrelated dopant incorporation and surface texturing mechanisms during fs-laser irradiation of Si coated with a Se thin-film dopant precursor. We show that the crystallization of Se-doped Si and micrometer-scale surface texturing are closely coupled and produce a doped surface that is not conducive to device fabrication. Next, we use this understanding of the dopant incorporation process to decouple dopant crystallization from surface texturing by tailoring the irradiation conditions. A low-fluence regime is identified in which a continuous surface layer of doped crystalline material forms in parallel with laser-induced periodic surface structures over many laser pulses. This investigation demonstrates the ability to tailor the dopant distribution through a systematic investigation of the relationship between fs-laser irradiation conditions, microstructure, and dopant distribution.