Preparation of hole array and dot array by holographic lithography system

The periodic array is fabricated on GaAs substrate by holographic lithography and wet etching. The double exposure for hole array in holographic lithography is adopted to optimized exposure time of 60s, and the optimal time of dot array is 80s. Wet etching solution with 1:1:10 volume ratio of H₃PO₄, H₂O₂ and H₂O is adopted to etch the hole array for 30 s, and to etch the dot array for 20 s. Images of scanning electron microscopy (SEM) show that the hole array and dot array has a period of 528 nm, with perfect surface morphology, good fringe continuity and uniformity.