Substrate and Defect Influences on the Position-Response Linearity of Position-Sensitive Detectors

The perfornmance of position¿sensitive detectors (PSD´s) witlh ani epilayer was investigated. Defects which are responsilble for a great position¿response nonlinearity in the p¿type resistive layer were fond. The influence of the substrate potential, the photocurrent generation in the junction between the epilayer and the substrate, and the dependency of the resistive layer thickness on the local potential were analyzed. By cornnecting the substrate to the same potential as the p¿type layer, distortions in the position¿response grid are reduced to a certain degree. A simple method was used to discover this kind of defect in an early stage.