Electrical contact with diffusion barrier
US5136362A · kind A · utility
Inventors
Key dates
| Filing date | Nov 27, 1990 |
| Grant date | Aug 4, 1992 |
| Priority date | — |
| Expiry date | Nov 27, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A device is provided by forming a diffusion barrier at the interface between a metalized contact and the surface of a semiconductor substrate. A three-layer sandwich is formed over the contact region and then annealed in free nitrogen. The sandwich is made of a titanium nitride layer interposed between layers of titanium. During the anneal, material from the titanium layer adjacent to the substrate migrates thereinto to produce a highly conductive diffusion region of titanium silicide. Concurrently during the anneal the other layer of titanium, which is exposed to the nitrogen atmosphere, is converted into a backing layer of titanium nitride which enhances the barrier effect of the titanium nitride layer at the center of the sandwich structure. The conversion of titanium to titanium nitride causes a physical expansion in the layer involved. This serves to enhance the thickness of the barrier layer at all locations, but of particular significance at the corners of the contact well. A diffusion region of controlled depth and the deposition of minimal amounts of titanium remote from the contact side itself are advantageous results of the disclosed process.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.