Evaluation and Optimization of a MOEMS Active Focusing Device

Area of Science:

• Optoelectromechanical Systems
• MEMS Technology
• Optical Engineering

Background:

• Micro-opto-electromechanical systems (MOEMS) offer potential for advanced optical functionalities.
• Active focusing mechanisms are crucial for high-performance imaging systems.
• Silicon membrane technology presents a promising platform for miniaturized optical devices.

Purpose of the Study:

• To conduct a detailed evaluation of a novel MOEMS device for active focusing.
• To investigate the impact of internal stress and process variations on device performance.
• To characterize the practical properties of the membrane focusing device for imaging applications.

Main Methods:

• Finite element method (FEM) simulations for theoretical analysis.
• Experimental characterization of the electrostatically deformed silicon membrane.
• Evaluation of device performance under varying process conditions and material stresses.

Main Results:

• The MOEMS device, realized in silicon-on-insulator (SOI) technology, exhibits controllable focal length.
• Internal stress, particularly from the buried oxide (BOX) layer, and stress gradients significantly influence device behavior.
• The device achieves high-performance imaging with wavefront errors between λ/5-λ/10 for a 5 mm aperture.

Conclusions:

• The proposed silicon membrane MOEMS is suitable for high-performance imaging applications.
• Understanding and mitigating stress effects are critical for optimizing device performance.
• The device demonstrates excellent long-term stability, controlled focal length, and dynamic response.