Rad-hard vertical JFET switch for the HV-MUX system of the ATLAS upgrade Inner Tracker

TL;DR

This paper introduces a new rad-hard vertical JFET switch designed for high-voltage applications in the ATLAS Inner Tracker upgrade, optimized through simulations and considering radiation effects for reliable operation.

Contribution

It presents a novel V-JFET device based on trenched 3D technology, with optimized characteristics and a SPICE model, specifically designed for high-radiation environments.

Findings

Optimized device parameters for low on-resistance and high breakdown voltage

Developed a SPICE model for circuit integration

Analyzed radiation damage effects on device performance

Abstract

This work presents a new silicon vertical JFET (V-JFET) device, based on the trenched 3D-detector technology developed at IMB-CNM, to be used as switches for the High-Voltage powering scheme of the ATLAS upgrade Inner Tracker. The optimization of the device characteristics is performed by 2D and 3D TCAD simulations. Special attention has been paid to the on-resistance and the switch-off and breakdown voltages to meet the specific requirements of the system. In addition, a set of parameter values has been extracted from the simulated curves to implement a SPICE model of the proposed V-JFET transistor. As these devices are expected to operate under very high radiation conditions during the whole experiment life-time, a study of the radiation damage effects and the expected degradation on the device performance is also presented at the end of the paper.