A high-speed MEMS grating laser scanner with a backside thinned grating platform fabricated using a single mask delay etching technique

Abstract

A novel micro-electromechanical system (MEMS) technology-based grating laser scanner with a backside thinned grating platform has been successfully developed for high-speed laser scanning applications. The grating platform is thinned by a round cavity and reinforced by a circular frame, which are fabricated using a single mask delay etching (SMDE) technique. The SMDE technique, which utilizes the well-know loading effects of the deep reactive ion etching (DRIE) process, is a simple and low-cost methodology to regulate the etching rate of a prescribed area. It can be used in a silicon-on-insulator (SOI) micromachining process to form multilevel structures in a silicon device layer through a multi-step DRIE process from a wafer's backside. This paper presents the design, simulation, fabrication process and characterization of the high-speed MEMS grating scanner as well as the principle and applications of the SMDE technique. When illuminated with a 635 nm wavelength incident laser beam, the prototype scanner with a 1 mm diameter diffraction grating is capable of scanning at 50.192 kHz with an optical scan angle of 14.1°. © 2010 IOP Publishing Ltd.