Speaker
Description
Silicon sensors are widely used in high-energy physics due to their low material budget and radiation hardness. However, they are susceptible to surface breakdown, particularly under humid conditions. This study aims to improve the understanding of the underlying mechanisms by developing new methods to probe the electric field at the sensor’s edge. For planar sensors, avalanche breakdown primarily occurs at the Si-SiO$_{2}$-interface, where localized electric field peaks can form between the guard ring and the edge. The local electric field is influenced by defects at the oxide surface and interface as well as the geometry of the sensor. Therefore, accurate simulations are challenging and it is essential to validate simulation parameters by comparing the simulation results to measurements.
In this work, the edge region of planar silicon diodes was simulated using Synopsis TCAD. Current, capacitance, and Transient Current Technique (TCT) simulations were performed and compared to measurements. Additionally, Allpix Squared simulations were used to determine whether the surface electric field at the edge can be extracted from top TCT measurements with 660 nm laser pulses using the prompt current method, similar to edge TCT.
