An electronic device includes a semiconductor substrate and a semiconductor surface layer having a first conductivity type, the semiconductor surface layer over the semiconductor substrate and having a top surface, a buried layer having an opposite second conductivity type between the semiconductor surface layer and the semiconductor substrate, a dielectric isolation layer that extends over and into the semiconductor surface layer, a deep trench structure that extends through the dielectric isolation layer into the semiconductor surface layer, and a silicide blocking layer on a top surface of the deep trench structure.