Office of Technology Transfer – University of Michigan

High spatial frequency femtosecond laser induced periodic surface structures for single crystal patterned semiconductors

Technology #6809

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Researchers
Michael J. Abere
Managed By
Joohee Kim
Licensing Specialist, Physical Sciences & Engineering 734.764.8202
Patent Protection
US Patent Pending

Surface corrugation is one of the most fundamental phenomena in materials science. The interaction between multiple intense ultrashort laser pulses and solids universally produces a regular surface corrugation. Laser induced periodic surface structures (LIPSS) are a form of corrugation produced by the use of light and they appear universally in metals, semiconductors, insulators. While a number of techniques are known for texturing semiconductor surfaces, they typically cause a breakdown of crystal quality during processing, which limits their effectiveness in devices. Improved technology on surface texturing that leads to retaining crystal structure for better semiconductor properties has the potential to open opportunities at semiconductor manufacturing equipment market that is estimated to be >$43.8 in size.

High spatial frequency laser induced periodic surface structures for single crystal patterned semiconductors

Materials Science Engineering researchers at the University of Michigan have proposed a method processing semiconductor surfaces by modifying the surface topography. The method is intended for patterning a semiconductor surface in a regular periodic fashion with features less than 200nm wide that retains a single crystal structure. The proposed method is product of a coupled mechanism that operates in a specific range of fluences in semiconductors between the band-gap collapse and ultrafast-melt thresholds that produces a unique corrugation known as high spatial frequency laser induced periodic surface structures (HSFL). The structures have period < 0.3 times the laser wavelength. HSFL formation is initiated when the intense laser field softens the interatomic binding potential, which leads to an ultrafast generation of point defects. The proposed method can be performed in air at ambient temperature and pressure. Through the use of this method, structures are predominately epitaxial single crystal which leads to better properties for effective use in devices. Control over such a mechanism opens the potential for ultrafast laser directed self-assembly.

Applications

  • Optoelectronics such as solar cells, LED’s and detectors
  • Doping semiconductors with exotic elements while simultaneously texturing a surface
  • interface free anti-reflective coatings

Advantages

  • Patterned surface retains a single crystal structure
  • Process can be performed in air at ambient temperature and pressure