Dry-etching Continuous Surface Profiles into Infrared Semiconductor Materials

摘要

Etching high efficiency diffractive optical elements (DOEs) into InSb substrates, using multiple binary masks, has proven to be problematic. This microfabrication method (sometimes. called binary optics technology) is time- consuming, costly and sensitive to alignment errors. Other major problems unique to InSb and the multi-mask process, are polymer buildup and substrate fracturing as a result of stresses experienced in subsequent etch levels. Since these do not appear to be problems with a single etch process, a new process is needed which achieves fabrication of high efficiency DOEs with only a single mask and a single etch step. This effort investigates the application of gray scale mask technology to etching high efficiency DOEs and micro-optical elements in InSb and InAs.