Characterization of silicon sensors measuring current versus voltage for the ATLAS Inner Tracker

In anticipation of the High-Luminosity phase of the LHC, the ATLAS experiment is working on major detector upgrades to prepare for the subsequent increase in radiation and track density. The largest of these upgrades is the replacement of the current tracking detectors with the Inner Tracker, or ITk. In the outer region of the ITk is the Strip Detector, which consists of silicon strip modules. Characterizing the electrical properties of the silicon strip modules at different stages of the assembly procedure is crucial to assessing module performance; this ensures any fault is captured at the earliest possible stage. One of the most important tests is the IV scan, which measures the silicon sensor current (I) as a function of voltage (V). Since the current as a function of voltage provides an indirect measure of the noise, the depletion voltage, and the breakdown voltage, IV scans allow us to determine whether the sensor performance is within specifications. This paper will summarize the IV scanning procedures I have developed and implemented, encompassing three stages of the module’s assembly. These procedures include the development of a novel IV scan using the Autonomous Monitor and Control chip, a custom ASIC mounted on each module. This will allow us to diagnose problematic modules after they are mounted on staves and in the ATLAS detector. I will also discuss my work on the configuration and analysis of these test results.