Patent ID: 9343459
Filing Date: 2016-05-17
CPC Classification: H01L

Claim Text:
1. A method of forming complementary PNP and NPN structures comprising: providing a p-type bulk semiconductor substrate; creating PNP and NPN active device regions; implanting buried N+ and P+ resurf regions in the PNP and NPN device regions respectively; implementing both the bulk semiconductor substrate and PNP and NPN device regions with single-crystal silicon; surrounding each transistor with deep trench isolation regions to isolate the complementary PNP and NPN structures from each other; performing a first masking operation and implanting a highly doped n-layer in the p-type bulk semiconductor substrate, wherein the highly doped n-layer is vertically under the PNP area and extends toward and touching the deep trench isolation; performing a second masking operation and implanting step performed after Pad Oxidation, before Nitride deposition to create a uniform collector doping level in the active device region; performing a third masking operation and etching step to provide a hard mask for defining a region of a shallow trench insulation layer STI in the active device region; forming deep trenches isolations, to encircle the PNP transistor and the highly doped n-layer, wherein the trenches extend below the bottom of the highly doped n-layer and extend to the top of die; implanting a p-type well extending through the STI layer and touching the collector of the active device layer with a collector contact coupled thereto; implanting a deep n-type well extending from the top of the wafer through the STI layer and the active device layer, touching the highly doped n-layer with a VCC contact coupled thereto; depositing a base epitaxial semiconductor layer, defining and doping with an impurity of the opposite conductivity type on top of the active device region with a base contact coupled thereto; and depositing an emitter region that covers a portion of the base epitaxial semiconductor layer, wherein the emitter region is highly doped with the same conductivity type as the active device region.