A MOSFET device structure and a method of manufacturing the same, in which a photon absorption layer is formed over a gate structure and a substrate in order to avoid plasma induced damage to the gate oxide during high density plasma deposition of a interlayer dielectric layer. The device structure may include an etch stop layer below the photon absorption layer. The photon absorption layer is formed entirely of silicon germanium or it may be a multi-layer formed of a silicon layer and a silicon germanium layer. In the multi-layer structure the silicon germanium layer may be formed on top of the silicon layer or vice-versa. The silicon germanium layer may be formed by implanting germanium ions into a silicon layer or by an epitaxial growth of the silicon germanium alloy layer. In the photon absorption layer the germanium may be substituted by another element whose band gap energy is less than that of silicon.