Provided is a method for fabricating a semiconductor device. In the method, a poly layer on a semiconductor substrate is etched to a predetermined depth. Ions are implanted into the poly layer at a predetermined angle. The poly layer is etched again to expose a portion of the semiconductor substrate. Therefore, stress is applied to the poly gate instead of the barrier layer, so that the barrier layer is not opened during contact etching because effects of the barrier layer thickness can be solved. Also, stress is applied to a poly gate directly contacting a channel region of the semiconductor substrate to allow tensile force caused by the stress of the poly gate to directly induce tensile force to the channel region, and thus increase mobility, so that device characteristics can be remarkably enhanced.