Fig. 1. Process flow of electron beam lithography GaAs-based micro-nano grating based on multilayer resist

Fig. 2. Schematic of electron scattering in electron beam lithography

Fig. 3. Influences of resists on pattern of grating photoresist mask. (a) PMMA A8 resists; (b) multilayer resist

Fig. 4. Surface view of SiO₂ hard mask

Fig. 5. Generation mechanism of grass phenomenon. (a) Gas ionization; (b) micro-mask generation; (c) micro-mask deposition; (d) etching

Fig. 6. Cross-sectional views of grating with different RF powers

Fig. 7. Effects of RF power on grating, grass structure, and SiO₂ hard mask. (a) Effects on grating etching depth and the ratio of grass structure depth to grating depth; (b) effects on GaAs and SiO₂ mask etching rate and SiO₂ mask thickness

Fig. 8. Spectrum of laser