It is understood that the parameters discussed herein can be tuned so that the implanted regions are effectively converted into amorphous regions regardless of the first species used. In addition, while the amorphous regions 219 are shown as being confined within the boundary of the first region 213, in some embodiments the amorphous regions 219 may extend over the first region 213. The depth of the amorphous regions 219 may vary depending upon the application, and can be controlled by changing the implantation energy, substrate temperature and/or the tilt angle.

After the amorphous regions 219 are formed in the exposed source/drain regions 292, a dopant implantation process may be performed to introduce a second species (e.g., dopants) to the exposed source/drain regions 292. The dopant implantation process is designed to further reduce the contact resistance to the source/drain regions 292. The contact resistance between the source/drain regions 292 and a conductive feature that is subsequently formed can be effectively reduced due to the characteristics of the second species. Particularly, due to the presence of large number of dangling bonds and random distribution of the first species (e.g., Ga) having a large atomic size in the amorphous regions 219, the majority of the second species can be trapped or confined within the amorphous regions 219. As a result, the dopant activation at the surface of the source/drain regions 292 can be greatly improved, and hence, further reduce the contact resistance for the devices.