| 摘要 |
<p>A method is provided for forming shallow lightly doped drain (LDD) (30) and source/drain junctions (34) without a spacer etch, which results in reduced junction resistance/capacitance and improved scalability. The method may also be extended easily to accommodate silicidation of source/drain regions for sub-micrometer integrated circuits. Essentially, a thin conformal film (28) is formed over the entire surface of a semiconductor substrate (10) after forming source/drain openings in the field oxide (12) and after forming the gate oxide (14) and metal gate (16) thereon. Implantation of the source and drain regions (32) simultaneously forms the LDD regions between the source/drain regions and the gate channel, due to the thickness of the thin film as it slopes from the top of the gate oxide/metal stack to the surface of the semiconductor substrate. The LDD junction is formed by one of three ways: (1) LDD implant before the thin conformal film deposition, (2) LDD implant after the thin conformal film deposition, and (3) diffusion from the phosphorus doped conformal thin film. In this latter case, the P ©& implant needs to be adjusted to compensate the phosphorus dopant in the P regions. In all three cases, the source/drain implant is always done after film deposition.</p> |
