Patent ID: 7459766

Claim:
A semiconductor device comprising: a bipolar transistor including; a first conduction type semiconductor substrate having a main surface; a second conduction type collector region formed in the semiconductor substrate; a shallow trench isolation structure for isolating the main surface of the semiconductor substrate into two active regions; a collector leading portion formed in one of the active regions; and a first conduction type base region and a second conduction type emitter region formed on the other one of the active regions, wherein the collector region has a first portion formed immediately below the shallow trench isolation structure and aligned with the shallow trench isolation structure and two second portions formed immediately below the two active regions and respectively aligned with the two active regions, wherein the first portion is formed at a first depth from the main surface and the two second portions are formed at a second depth from the main surface, with the first depth being less than the second depth, and wherein the two second portions are formed at substantially the same depth.