A semiconductor structure includes a semiconductor substrate, and an NMOS device at a surface of the semiconductor substrate, wherein the NMOS device comprises a Schottky source/drain extension region. The semiconductor structure further includes a PMOS device at the surface of the semiconductor substrate, wherein the PMOS device comprises a source/drain extension region comprising only non-metal materials. Schottky source/drain extension regions may be formed for both PMOS and NMOS devices, wherein the Schottky barrier height of the PMOS device is reduced by forming the PMOS device over a semiconductor layer having a low valence band.