Some embodiments of the present disclosure relate to an implant that improves long-channel transistor performance with little to no impact on short-channel transistor performance. To mitigate DIBL, both long-channel and short-channel transistors on a substrate are subjected to a halo implant. While the halo implant improves short-channel transistor performance, it degrades long-channel transistor performance. Therefore, a counter-halo implant is performed on the long-channel transistors only to restore their performance. To achieve this, the counter-halo implant is performed at an angle that introduces dopant impurities near the source/drain regions of the long-channel transistors to counteract the effects of the halo implant, while the counter-halo implant is simultaneously shadowed from reaching the channel of the short-channel transistors.