Provided is a transistor and a method for forming a transistor in a semiconductor device. The method includes performing at least one implantation operation in the transistor channel area, then forming a silicon carbide/silicon composite film over the implanted area prior to introducing further dopant impurities. A halo implantation operation with a very low tilt angle is used to form areas of high dopant concentration at edges of the transistor channel to alleviate short channel effects. The transistor structure so-formed includes a reduced dopant impurity concentration at the substrate interface with the gate dielectric and a peak concentration about 10-50 nm below the surface. The dopant profile also includes the transistor channel having high dopant impurity concentration areas at opposed ends of the transistor channel.