  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
