Silicon controlled rectifier with stress-enhanced adjustable trigger voltage

A device structure formed using a semiconductor substrate having a top surface, the device structure comprising:

• a silicon controlled rectifier (SCR) including an anode, a cathode, a first well in the semiconductor substrate and having a first conductivity type, and a second well in the semiconductor substrate and having a second conductivity type opposite to the first conductivity type, the first well and the second well disposed in a current-carrying path between the anode and the cathode;
• a first stress layer on the top surface of the semiconductor substrate, the first stress layer located at a position on the top surface of the semiconductor substrate and configured to cause a first mechanical stress in the first well at a level sufficient to modulate a trigger current of the SCR;
• and
• a second stress layer on the top surface of the semiconductor substrate, the second stress layer configured to transfer a second mechanical stress to the second well,
• wherein the first mechanical stress and the second mechanical stress have opposite polarities selected from tensile stress or compressive stress.