A small distortion two-dimensional position-sensitive detector (PSD) with on-chip MOSFET switches

The authors describe a two-dimensional position-sensitive detector (PSD) device. The device has a structure analogous to a tetralateral 2D-PSD but has on-chip MOSFET switches at the edges of the sensing area which make the detection principle equivalent to that of a 1D-PSD. This results in a linearity of position sensing in the 2D-PSD as good as that in the 1D-PSD. The integrated MOSFET´s performance and position-detection characteristics were experimentally investigated. The position nonlinearity of the output signal was found to be drastically reduced from 7% in the conventional operation to 0.02% in the MOSFET switching operation. The maximum operating frequency of the MOSFETs was about 5 kHz for this prototype device. The device is expected to be useful for precise two-dimensional light beam detection over a large sensing area.<>