Silicon controlled rectifiers

A structure comprising:

• a first well in a semiconductor substrate and electrically coupled to an anode;
• a second well in the semiconductor substrate and electrically coupled to a cathode;
• and
• at least one vertical gate structure extending vertically within the semiconductor substrate and which sits between the anode and the cathode,
• wherein the at least one vertical gate structure comprises a plurality of vertical gate structures sitting within the second well.

A method comprising:

• forming a first well in a semiconductor substrate;
• forming a second well in the semiconductor substrate, adjacent to the first well;
• forming a plurality of shallow trench isolation structures extending into the first well and the second well;
• and
• forming at least one vertical gate structure in the first well which abuts one shallow trench isolation structure of the plurality of shallow trench isolation structures, and below a bottom surface of the first well.