Fabrication and characterization of a clover type position sensitive detector

A new type of lateral-effect position-sensitive photodetector (PSD) has been fabricated on silicon using standard IC technology. The new geometry is called a clover PSD. The experimental performance of tetralateral, pin-cushion, and clover PSDs is compared in terms of measurement linearity and sensitivity. The distortion in linearity is more severe than the simulated values in every case, since the diffused layers in the devices were not uniform. It is observed that the clover PSD has better linearity than both pin-cushion and tetralateral PSDs. The sensitivity of the clover PSD is found to be twice as high as that of the pin-cushion PSD, whereas theory predicts a five times improvement. The discrepancy is explained in terms of the much higher sensitivity of the clover PSD to contact and external parasitic resistances