US 12,113,125 B2
Bipolar transistor having collector with doping concentration discontinuity
Kai Hay Kwok, Burlington, MA (US); Cristian Cismaru, Newbury Park, CA (US); Andre G. Metzger, Newbury Park, CA (US); and Guoliang Zhou, Walpole, MA (US)
Assigned to Skyworks Solutions, Inc., Irvine, CA (US)
Filed by Skyworks Solutions, Inc., Irvine, CA (US)
Filed on Jun. 29, 2022, as Appl. No. 17/809,855.
Claims priority of provisional application 63/217,133, filed on Jun. 30, 2021.
Claims priority of provisional application 63/217,116, filed on Jun. 30, 2021.
Prior Publication US 2023/0006055 A1, Jan. 5, 2023
Int. Cl. H01L 29/737 (2006.01); H01L 29/08 (2006.01); H01L 29/20 (2006.01)
CPC H01L 29/7371 (2013.01) [H01L 29/0821 (2013.01); H01L 29/20 (2013.01)] 28 Claims
OG exemplary drawing
 
1. A bipolar transistor comprising:
an emitter;
a base; and
a collector having a first collector region and a second collector region, the first collector region between the base and the second collector region, the first collector region having a flat doping concentration, the second collector region having a graded doping concentration that increases along a direction away from the base, a transition from the flat doping concentration of the first collector region to the graded doping concentration of the second collector region having a step increase in the doping concentration, the collector having an additional collector region between the base and the first collector region, and the additional collector region having a doping concentration that is higher than the doping concentrations of the first collector region and the second collector region.