Short-channel threshold voltage roll-off and punchthrough in an IGFET (40 or 42) having a channel zone (64 or 84) situated in body material (50) are alleviated by arranging for the net dopant concentration in the channel zone to longitudinally reach a local surface minimum at a location between the IGFET's source/drain zones (60 and 62 or 80 and 82) and by arranging for the net dopant concentration in the body material to reach a local subsurface maximum more than 0.1 &mgr;m deep into the body material but not more than 0.4 &mgr;m deep into the body material.