The halo implant technique described herein employs a halo implant mask that creates a halo implant shadowing effect during halo dopant bombardment. A first transistor device structure and a second transistor device structure are formed on a wafer such that they are orthogonally oriented to each other. A common halo implant mask is created with features that prevent halo implantation of the diffusion region of the second transistor device structure during halo implantation of the diffusion region of the first transistor device structure, and with features that prevent halo implantation of the diffusion region of the first transistor device structure during halo implantation of the diffusion region of the second transistor device structure. The orthogonal orientation of the transistor device structures and the pattern of the halo implant mask obviates the need to create multiple implant masks to achieve different threshold voltages for the transistor device structures.