Photoelectrochemical Etching of Blazed Eschelle Gratings in n-GaAs

摘要

Photoelectrochemical etching can be a technique for producing microstructures in semiconductors with a high aspect ratio and excellent lateral uniformity. We had demonstrated previously that symmetrical V-groove Eschelle diffraction gratings, used in a variety of spectrometers and opto-electronic devices, can be fabricated by photoanodic dissolution of (100) oriented GaAs, using a Ronchi ruling photoresist mask. In this paper, we report the etching of blazed Eschelle gratings of 15 x 15 mm dimensions and with 50 cycles/mm. To do this, n-GaAs crystals were sliced with a (100)-n orientation, with respect to the (011) plane. By varying the angle n, gratings with blaze angles of 45, 53 and 60 have been demonstrated. In situ coulometry was used to monitor the etching process and to determine when the grating reached completion. SEM and optical measurements of the blaze angles of the completed gratings were in close agreement. Etching, Photoelectrochemical, Grating, Gallium Arsenides. (MJM)