Patent ID: 7015077

Claim:
A method of manufacturing a semiconductor device having a semiconductor substrate with an upper surface, the method comprising: etching the substrate and forming a shallower trench portion and a deeper trench portion, the deeper trench portion extending deeper into the substrate than the shallower trench portion; forming a thyristor having a body and a control port, the body including an emitter region in the substrate and below the upper surface, the control port being at least in the shallower trench portion and capacitively coupled to the body; and forming a pass device having first and second source/drain regions separated by a channel region and a gate capacitively coupled to the channel region and adapted to control current flow between the source/drain regions, the first source/drain region being coupled to the emitter region; wherein etching the substrate further includes etching a shallow trench isolation (STI) region in the substrate, wherein etching the substrate and forming a deeper trench portion includes etching the deeper trench portion in a portion of the substrate below the STI region, wherein etching a STI region includes forming the STI region to electrically isolating the pass device and the thyristor from adjacent circuitry in the substrate.