Method of forming self-aligned contact openings

Claim 1

In a process for forming a self-aligned contact opening in a semiconductor device, the device having a semiconductor substrate of a first conductivity type, a gate insulator layer formed on the surface of the substrate, a gate member formed on a portion of the surface of the insulator layer, a source region and a drain region of a second opposite conductivity type formed in the substrate at the surface thereof and having their facing edges aligned with the edges of the gate member, the gate member and the remainder of the gate insulator layer being covered with a second insulator layer, the improved process comprising the following steps, in the following order: forming openings in the second insulator layer and in the gate insulator layer to expose a portion of the source region, a portion of the drain region and a portion of the gate member, wherein, after etching, any misalignment of the apertures, with respect to the source and drain regions, exposes portions of the substrate adjacent the source and/or drain regions; implanting a second type conductivity modifier through the apertures into the source and drain regions and into any exposed area of substrate; heating the substrate to anneal implantation damage and to cause the implanted conductivity modifiers to migrate laterally and deeper into the substrate; and depositing conductive material into the apertures to form ohmic contacts with the source and drain regions, the gate member and any previously exposed area of substrate.