A HV Silicon Vertical JFET: TCAD Simulations

In the future ATLAS Inner Tracker detector (ITk), several silicon strip modules will be biased by a single High-Voltage (HV) line, so that a switch between each strip sensor and the HV line is required to disconnect faulty sensors. Such a switch must satisfy strict requirements, such as being radiation hard, being able to sustain high voltages in the OFF state and being able to operate in a high magnetic field. At Brookhaven National Laboratory we conceived a new kind of solid-state switch that can potentially meet all the specs: it is a HV silicon vertical JFET. Before designing and fabricating the JFET, we did a study using numerical TCAD simulations that demonstrate the feasibility of fabricating the device in a standard planar technology. We report such simulations, highlighting in particular a few key parameters to which the JFET performances are most sensitive.