A resonance scanning grating based on SOI for microspectrometer application

摘要

A scanning grating is designed and fabricated as a significant dispersing component of a microspectrometer. The designed scanning grating utilizes the slight vertical comb offsets induced mainly by the fabrication imperfections and residual stress in silicon on insulator (SOI) as starting electrodes. According to the spectral resolution and resonance frequency requirements, the scanning grating structure parameters are determined. Based on an SOI substrate, a V-shaped grating structure (h111) plane with an angle of 54.74o to the surface of a h100i silicon substrate) can be obtained by wet etching on the microscanning mirror plate (3 × 3 mm~2). Some measuring principles and experimental results on the main performance of the scanning grating including the resonance frequency, deflection angle and diffraction efficiency are discussed in detail. The mechanical deflection angle of the scanning grating can reach ±5°, corresponding to an optical scan range of 20o at a driving voltage of 30 V.