The source/drain zones (140 and 142 or 160 and 162) of a p-channel IGFET (120 or 122) are provided with graded-junction characteristics to reduce junction capacitance, thereby increasing switching speed. Each source/drain zone contains a main portion (140M, 142M, 160M, or 162M) and a more lightly doped lower portion (140L, 142L, 160L, or 162L) underlying, and vertically continuous with, the main portion.