Patent ID: 7157342

Claim:
A method of fabricating a semiconductor device, comprising: forming sidewalls in masking material over semiconductor material to define a window; conditioning the masking material over the semiconductor material; implanting first-type dopant in the semiconductor material for a base region to each of first and second thyristors for a mirror image pair, the implanting affecting substantially identical lateral extents to the base regions in the semiconductor material relative to the sidewalls of the conditioned masking material; and implanting second-type dopant into regions of the semiconductor material aligned to the sidewalls defining the window, and forming an emitter region for the thyristors with a lateral extent less than that for the base regions and substantially symmetrically therein; in which: the implanting with the first-type dopant for the base regions comprises directing the first type dopant toward the semiconductor material per an angle of incidence relative to a plane defined by a surface of the semiconductor material per an acute angle of incidence that is less than 60 degrees; and the implanting with the second-type dopant for the emitter region comprises directing the second-type dopant toward the semiconductor material using an angle of incidence of 75 to 105 degrees relative to the plane.