Patent ID: 7358545

Claim:
A bipolar junction transistor, comprising: a first conductive type substrate; a second conductive type emitter disposed in the first conductive type substrate; a first conductive type well disposed in the first conductive type substrate, wherein the first conductive type well surrounds the emitter and connects with the bottom of the emitter to serve as a base; a second conductive type well disposed in the first conductive type substrate, wherein the second conductive type well surrounds the base; a second conductive type deep well disposed in the first conductive type substrate, wherein the second conductive type deep well connects with the bottom of the base and connects with the bottom of the second conductive type well to serve as a collector; an isolation structure disposed between the emitter and the base and between a portion of the base and a portion of the second conductive type well; a buffer region disposed under a portion of the isolation structure, wherein the buffer region and a portion of the isolation structure together isolates the base from the second conductive type well; a second conductive type collector pick-up region, wherein the second conductive type collector pick-up region connects with the second conductive type well and surrounds the first conductive type well; and a first conductive type base pick-up region, wherein the first conductive type base pick-up region connects with the base and surrounds the emitter.