Computational modelling of semiconducting X-ray detectors

The design of high-performance semiconductor detectors is dominated by requirements on position and energy resolution and speed of operation. We investigate the contribution that three-dimensional transient device modelling can make to understanding these and the potential for its use in the design cycle. tions are performed using the EVEREST software to solve the drift-diffusion equations. Extra functionality has been added to allow the generation of electron–hole pairs by, for example, the absorption of an X-ray. Careful time integration can measure the time of arrival of the charge packet at the collecting well. e integrating the current arriving in the collecting well the spatial distribution of charge can be determined. A simple analytic theory is developed and compared with simulations of a large pixel detector. Comparisons with simulations of a two pixel device show that the analytic approximation is reasonable if the X-ray is absorbed beyond 100 μm from the well, but events closer show a marked deviation.