Integrated position sensing for 2D microscanning mirrors using the SOI-device layer as the piezoresistive mechanical-elastic transformer

Position feedback of resonant scanning micromirrors plays a key role for various applications like portable laser projection displays or scanning grating spectrometers. The SOI device layer without an additional surface implantation is used for the piezoresistive sensor design. It assures the full compatibility to microscanner technology and requires no additional technological efforts. The necessary asymmetry of the current field density is achieved by the geometrical design of the sensor and its contacting. Integrated 2D position sensors with amplitude sensitivities of 0.42mV/V° were fabricated. FEA simulation and measured data correlates well with variations of <= 20.4%.