Embodiments of the disclosure provide an integrated circuit (IC) structure, including a doped well in a semiconductor substrate, in addition to a base region, emitter region, and collector region in the doped well. An insulative material is within the doped well, with a first end horizontally adjacent the collector region and a second end opposite the first end. A doped semiconductor region is within the doped well adjacent the second end of the insulative material. The doped semiconductor region is positioned to define an avalanche junction between the collector region and the doped semiconductor region across the doped well.