Electromagnetic force-driven pull-up growth of surface-melted silicon by laser irradiation and resistive heating current

Abstract A silicon (Si) wafer was heated using concurrent laser irradiation and a heating current under static electric and magnetic fields. Si melted locally near the laser irradiation point, flowed, and accumulated on the surface along the direction dictated by the Lorentz force. Electric stress exceeding surface tension pulled the melt upward, forming a protrusion with an apex surrounded by facets. The apex of the protrusion grown at −10 kV exhibited {001}, {113}, and {111} facets, whereas the apex of the protrusion grown at −13 kV featured small protrusions with faceted surfaces. In contrast, the apex of the protrusion formed solely under a magnetic field was neither faceted nor sharp. This study demonstrates that static electric and magnetic fields applied during laser and resistive heating effectively control melt growth, offering potential for precise material structuring.