SIU GaAs is characterized by an imperfect drift of charge carriers, due probably to trapping [10] and to the peculiar shape of the electric field. Double-sided microstrip detectors show a marked asymmetry in charge response from the two sides [11]. Therefore a full 2-dimensional simulation of the charge drift in the device is needed in order to calculate the signal induced on the strips.
Figure 1: Block diagram of the codes used for microstrip detector simulation.
Input parameters are in ellipses.
The chain of programs used is shown schematically in fig. 1. The three main parts are: a program to calculate the electric fields, one to simulate the drift of electrons and holes, and finally a SPICE calculation of the response of the front-end network. Each of these parts will be considered separately.