Zener diode structures and related fabrication methods and semiconductor devices are provided. An exemplary semiconductor device includes first and second Zener diode structures. The first Zener diode structure includes a first region, a second region that is adjacent to the first region, and a third region adjacent to the first region and the second region to provide a junction that is configured to influence a first reverse breakdown voltage of a junction between the first region and the second region. The second Zener diode structure includes a fourth region, a fifth region that is adjacent to the fourth region, and a sixth region adjacent to the fourth region and the fifth region to provide a junction configured to influence a second reverse breakdown voltage of a junction between the fourth region and the fifth region, wherein the second reverse breakdown voltage and the first reverse breakdown voltage are different.