A device and a method for forming a device are disclosed. The method includes providing a substrate prepared with a device region. A device well having second polarity type dopants is formed in the substrate. A threshold voltage (VT) implant is performed with a desired level of second polarity type dopants into the substrate. The VT implant forms a VT adjust region to obtain a desired VT of a transistor. A co-implantation with diffusion suppression material is performed to form a diffusion suppression (DS) region in the substrate. The DS region reduces or prevents segregation and out-diffusion of the VT implanted second polarity type dopants. A transistor of a first polarity type having a gate is formed in the device region. First and second diffusion regions are formed adjacent to sidewalls of the gate.