On-chip frequency tuning of fast resonant MEMS scanner

TL;DR

This paper presents a high-frequency MEMS scanner with on-chip electrothermal tuning that allows precise control of resonant frequency and scan pattern, enabling high-speed 2D scanning with full angular range.

Contribution

The development of a dual-mode resonant MEMS scanner with integrated electrothermal tuning for frequency adjustment is a novel advancement.

Findings

Resonant frequency exceeds 140 kHz with 10° and 6° scan angles.

Achieved tuning range of up to 5.5 kHz on one mode.

Full frame update rates up to 20 kHz with maintained angular range.

Abstract

The development and characterisation of a piezoelectric actuated high-frequency MEMS scanning mirror with on-chip frequency tuning capability is reported. The resonant scanner operates at frequencies in excess of 140 kHz, generating scan angles of 10{\deg} and 6{\deg} for two orthogonal movement modes with 40 V actuation. On-chip frequency tuning is achieved through electrothermal actuators fabricated adjacent to the mirror main suspension. The electrothermal actuators produce a global and local temperature increase which changes the suspension stiffness and therefore the resonant frequency. A resonance frequency tuning range of up to 5.5 kHz is achieved, with tuning dominant on only one of the two orthogonal scan movement modes. This opens the possibility for precise tuning of a 2D Lissajous scan pattern using a single resonant MEMS scanner with dual orthogonal resonant modes producing full frame update rates up to 20 kHz while retaining the full angular range of both resonant movement modes