This letter describes a transient phenomenon in the reverse hole current of large-area shallow n+–p-well junctions, giving rise to a hump at a specific reverse bias. This corresponds to a certain depletion depth in the retrograde p well, which has been fabricated by a deep (200 keV) and a shallow (55 keV) boron ion implantation. No such a reverse hole current hump occurs for reference diodes, processed in p-type Czochralski substrates. The effect is also absent in large-perimeter p-well junctions, suggesting a correlation with defects in the p-well region. The occurrence at a specific depletion depth indicates a nonuniform defect distribution, for example related to the displacement damage created by the 200 keV B implantation. This idea is further supported by deep level transient spectroscopy results, which reveal the presence of a nonuniform density of hole traps, corresponding to a broad range of energy levels from about 0.3 to 0.5 eV above the valence band. A discussion of the possible nature of the underlying defects is given. © 2001 American Institute of Physics.