The line plot is from the EPD signal of scans made of bipolar structures.
The two lower figures show cross-sections of the doping profiles for the
(G)ood and (F)ailing devices.  Both devices were fabricated on p-type
silicon.  The n-well and outermost n+ implants common to both structures
are clearly seen.  The inner profiles differ due to the missing p-well
and p+ implants from the failing device.