Patent ID: 8889520

Claim:
A method of forming a plurality of bipolar junction transistors, comprising: implanting first type dopant into a semiconductor material to form a first type doped region; forming first trenches along a first direction within the first type doped region to a first depth; filling the first trenches with one or more electrically insulative materials; forming second trenches along a second direction within the first type doped region to a second depth which is deeper than the first depth, the second direction intersecting the first direction; filling the second trenches with one or more electrically insulative materials; an array of pedestals of the semiconductor material being patterned by the forming of the first and second trenches; after forming the array of pedestals, counter-doping an upper portion of the first type doped region to form a first stack comprising a second type doped region over a first type doped region; counter-doping an upper portion of the first stack to form a second stack comprising a second type doped region between a pair of first type doped regions; one of the first type doped regions being a top region of the second stack and the other of the first type doped regions being a bottom region of the second stack; wherein the first trenches extend only partially through the second type doped region; wherein the second trenches extend entirely through the second type doped region but only partially through the bottom region of the second stack; and wherein one of the first and second types is p-type and the other is n-type.