A method of forming a semiconductor device includes forming a row of n-type wells and p-type wells in an upper surface of a semiconductor body, the p-type wells arranged alternatingly with the n-type wells, forming trigger regions in between the n-type wells and the p-type wells, the trigger regions including a low-doped section of the semiconductor body that is configured to induce current flow between the p-type wells and the n-type wells via avalanche breakdown, wherein the p-type wells and the n-type wells are formed by implanting dopant atoms into the upper surface of the semiconductor body, and wherein the low-doped section of the semiconductor body is formed by a hardmask that prevents the dopant atoms from penetrating the upper surface of the semiconductor body during the implanting of the dopant atoms.