Patent ID: 6797577
Filing Date: 2004-09-28
Classification: H01L

Abstract:
A method of forming a PNP bipolar transistor, comprising:forming four isolation regions in an n-type semiconductor material, thereby defining a first, second and third region between the four isolation regions, respectively; forming and patterning a first mask to expose two laterally separated openings over the n-type semiconductor material, the two openings corresponding to the first and third regions in the n-type semiconductor material; performing a P-well implant using the first mask to form two laterally separated P-well regions within the n-type semiconductor material; removing the first mask; forming and patterning a second mask to expose an opening over the second region between the first and third regions; performing a p-type custom collector region implant different than the P-well implant using the second mask into the second region, thereby forming a custom collector region contacting the P-well regions under the second and third isolation regions, respectively to collectively form a collector region of the PNP bipolar transistor; performing an n-type base implant using the second mask, thereby forming an n-type base region in the custom collector region.