Position sensitive light detectors with high linearity

Abstract

The position linearity of position sensitive light detectors (PSD) of various designs was investigated. It was shown that existing detectors suffered from inherent nonlinearities. The maximum distortion was in the range of 35-40 percent within the center 64 percent of the active area. Design and fabrication of a detector with extremely high position linearity was described. By using a double-sided construction and by careful matching of the process parameters a maximum distortion of /spl sime/0.2 percent was attained within 100 percent of the active area. Finally, factors influencing the practically attainable linearity were analyzed.