基于时空整形的超快激光碳化硅深亚波长纳米刻蚀技术研究OA

Femtosecond-laser-induced self-organized interference,together with near-field enhancement and incubation effects,enables deep-subwavelength nanoetching.However,the formation of such structures usu-ally relies on random surface scattering centers and multi-pulse feedback,leading to poor uniformity,limited repeatability,and high sensitivity to laser parameters.In this work,a spatiotemporal laser-energy modulation strategy is proposed to improve the writing quality of nanogrooves on 4H-SiC single-crystal surfaces.In the spatial domain,single-slit and double-slit beam shaping are employed to reconstruct the focal-plane energy distribution,suppress lateral energy spreading,and enhance the incubation and self-organized interference ef-fects.In the temporal domain,a GHz burst mode is introduced to regulate the energy-deposition sequence,re-duce the instantaneous energy-deposition intensity,and extend the annealing time.Static irradiation and dy-namic scanning experiments were conducted to systematically investigate the surface morphology evolution and nanogroove formation mechanism under different modulation strategies.The results show that the ellipt-ical focal spot formed by single-slit shaping enhances the incubation and annealing effects,producing nanogrooves with improved uniformity and edge regularity and a minimum groove width of 62 nm.Double-slit shaping further strengthens the interference-field confinement,reduces the dependence of nanogroove formation on random scattering centers,and decreases the minimum controllable groove width to 34 nm.By introducing GHz burst pulses on the basis of double-slit shaping,stepwise energy deposition through sub-pulses with a 400 ps interval reduces instantaneous strong excitation and suppresses molten redeposition and particle attachment,further decreasing the minimum controllable groove width to 24.5 nm.This spatiotem-poral modulation strategy provides an effective technical approach and theoretical basis for high-precision,low-damage,and highly repeatable nanomanufacturing on third-generation semiconductor surfaces.