Design and development of two-dimensional position sensitive photo-detector
Position sensitive photo-detectors (PSDs) utilize the lateral photovoltaic effect to produce an electrical output that varies linearly with the position of a light spot incident on a semiconductor junction. Design, fabrication and characterization of newly developed silicon PSD, which employ the planar technology and double ion implantation with different doses, are described. Shallow and low-doped pn junction is formed by boron implantation in n-type silicon substrate. The position characteristics of PSD are symmetric to the zero and linear in the 80% of the active area. For a higher resistivity top layer (lower implanted dose), the sensitivity grows up and the linearity gets improved. The influence of the substrate is not substantial for the position characteristics. The response of the sensor, measured by pulsed 15ns laser, was determined to be about 100ns. Described PSD has been used in the construction of simple light spot rotational follower.
silicon position sensitive detector majority carriers