Patent ID: 7176548

Claim:
A bipolar transistor arrangement comprising: a substrate of a first conductivity type; an epitaxial layer of a second conductivity type formed on said substrate; a first vertical bipolar transistor comprising: a first buried layer of said second conductivity type located at an interface between said substrate and said epitaxial layer; a second buried layer of said first conductivity type at said interface, said second buried layer extending upward into said epitaxial layer beyond said first buried layer, said first buried layer extending laterally beyond said second buried layer; a first sinker of said second conductivity type extending downward from a surface of said epitaxial layer to said first buried layer; a first isolation region of said first conductivity type extending downward from said surface of said epitaxial layer to said second buried layer; and a first region of said first conductivity type at said surface of said epitaxial layer, said first region being separated from said second buried layer by a first area of said epitaxial layer; a second vertical bipolar transistor comprising: a third buried layer of said second conductivity type at said interface; a second sinker of said second conductivity type extending downward from said surface of said epitaxial layer to said third buried layer; a second region of said second conductivity type located at said surface of said epitaxial layer; and a third region of said first conductivity type located at said surface of said epitaxial layer and forming a junction with said second region, and a first isolation structure comprising: a fourth buried layer of said first conductivity type located at said interface and located between said first and third buried layers; and a second isolation region of said first conductivity type extending downward from said surface of said epitaxial layer to said fourth buried layer; wherein each of said first and second sinkers and said first and second isolation regions, respectively, is located at least partially in a mesa between a pair of trenches, said trenches being substantially filled with a dielectric material.