Two-dimensional position-sensitive photodetector with high linearity made with standard i.c.-technology

Abstract

Based on the lateral photoeffect it is possible to construct photodetectors of which the output is dependent on the light-spot position. In the literature, a number of these position-sensitive detectors (p.s.d.) based on the forward or reverse characteristics of a photodiode have been presented. The integration of a p.s.d. with signal processing circuits on one silicon chip may eventually lead to very versatile, high-quality low-cost sensors. Therefore it is necessary to develop a p.s.d. structure which can be fabricated with standard planar silicon technology. In this paper such a novel reverse-biased p.s.d. structure is presented. A 6 × 6 mm2 p.s.d. was made, and an overall linearity better than 0.5% full scale and a photosensitivity of 0.5 A/W for an He-Ne laser were obtained. The dependence of the position sensitivity on background illumination and temperature as well as resolution are similar to those of currently known linear p.s.d.s.