| CPC H01L 29/747 (2013.01) [H01L 29/083 (2013.01); H01L 29/1012 (2013.01); H01L 29/66386 (2013.01)] | 17 Claims |

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1. A method of making a semiconductor device, the method comprising:
doping to create an upper base region associated with a first side of a substrate of semiconductor material;
etching the first side to create an upper-CE trench, the upper-CE trench defines a proximal opening at the first side and a distal end within the substrate;
doping through the distal end of the upper-CE trench to create an upper collector-emitter region;
doping to create a lower base region associated with a second side of the substrate; and
doping to create a lower collector-emitter region associated with the second side.
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