Disclosed are methods of forming a semiconductor device, such as a finFET device. One non-limiting method may include providing a semiconductor device including a substrate and a plurality of fins extending from the substrate, and forming a source trench isolation (STI) material over the semiconductor device. The method may further include performing a fin cut by removing a first fin section of the plurality of fins and a first portion of the STI material, and forming a second STI material over a second fin section of the plurality of fins, wherein the second fin section is left remaining following removal of the first fin section. The method may further include recessing the STI material and the second STI material, forming a spin-on-carbon (SOC) layer over the semiconductor device, and implanting the STI material and the second STI material through the SOC layer.