Simulations of Inter-Strip Capacitance and Resistance for the Design of the CMS Tracker Upgrade

An upgrade of the LHC accelerator, the high luminosity phase of the LHC (HL-LHC), is foreseen for 2023. The tracking system of the CMS experiment at HL-LHC will face a more intense radiation environment than the present system was designed for. This requires an upgrade of the full tracker, which will be equipped with higher granularity as well as radiation harder sensors, which can withstand higher radiation levels and occupancies.\\ In order to address the problems caused by the intense radiation environment, extensive measurements and simulation studies have been initiated for investigating these different design and material options for Silicon micro-strip sensors.\\ The simulation studies are based on commercial packages (Silvaco and Synopsys TCAD) and aim to investigate sensor characteristics before and after irradiation for fluences up to $1.5 \cdot 10^{15}\,\rm{n_{eq}/cm}^2$. A defect model was developed to implement the radiation damage and tuned to fit experimental measurements.\\ This paper covers the simulation of the inter-strip capacitance and resistance both before and after irradiation. Both properties are crucial for the design of future sensors, being responsible for strip noise and isolation, in turn affecting resolution. A detailed understanding of these parameters is required for an optimal sensor design for the future CMS tracker.