Abstract:
One of the core processes of semiconductor distributed feedback lasers was the fabrication of distributed feedback gratings, and the first-order Bragg grating structure of 808 nm distributed feedback semiconductor was designed. A trapezoidal grating structure with a period of 120 nm was fabricated by using nanoimprint technology combined with process of dry etching and wet etching. The optical field distribution and energy band diagram of epitaxial structure were simulated using MATLAB and Pics3D software. The ideal wet etching process parameters were obtained by optimizing the proportions of corrosion components used in wet etching, corrosion temperature and corrosion time. The scanning electron microscopy measurement shows that the grating has a period of 120 nm, depth about 85 nm, duty cycle about 47%, and the grating has the advantages of straight edges, smooth surface and even period. The innovative introduction of the wet etching process and the corrosion sacrificial layer ensures the cleanliness of the grating surface, improves the secondary epitaxial quality, which lays a good foundation for the further production of high-performance chips for distributed feedback lasers.