In situ monitoring technique for fabrication of high-quality diffraction gratings

We describe a simple technique that permits reproducible fabrication of high-quality diffraction gratings with short periods. This technique utilizes in situ monitoring of diffracted light from photoresist gratings during the development process and provides optimum endpoint detection for this process. The effectiveness of the technique has been demonstrated through the fabrication of a distinct grating with a 255-nm period on a GaAs substrate.