A new method to repair ion implantation-induced damage in the gate dielectric layer of MOSFETs

As device feature sizes continue to scale down, tilted ion implantation technology is widely used in CMOS fabrication process to place ions under the gate for various purposes, including short-channel effects (SCE) control and resistance reduction in the overlap region. However, during the tilted ion implantation process, ions go through the edge region of the gate dielectric layer of the device, which might lead to damage of the gate dielectric layer when ion dose and energy are high. The damage of the gate dielectric layer manifests as significantly increased gate leakage, thus eventually leading to device failure. This paper provides a new method to repair the ion implantation caused damage to the dielectric layer of MOSFETs: performing wet etch to remove the damaged edge part of the gate dielectric and then refilling the edge part of the gate dielectric by chemical vapor deposition (CVD) or atomic layer deposition (ALD).