The use of III-V compound semiconductors has been widely explored as a means to improve integrated circuit performance.
Various metal layers have been used as semiconductor device contacts due to their good electrical properties and relatively high thermal stability. For example, a Ni—InGaAs source/drain contact scheme for III-V metal-oxide-semiconductor field effect transistors (MOSFET) has been developed. The Ni—InGaAs layer may be formed, for example, onto an exposed surface of source and drain regions in a semiconductor substrate. During an annealing process, atoms of the substrate in the source and drain regions react with the atoms of the deposited metal, thereby forming a layer. Portions of the un-reacted metal on insulating regions can be selectively removed. The remaining layer can reduce sheet resistance/sheet resistivity at the source/drain contact by helping to form a highly conductive metal layer on the semiconductor so that good electrical contact can be made.
As devices scale smaller, contact resistance generally increases. To facilitate implementation of III-V semiconductors, the practical matter of contacts with devices must be addressed to avoid, for example, increased parasitic resistance in series with source and drain regions as semiconductor structures are scaled down in size. This is particularly true because series resistance degrades device performance by, for example, decreasing drain current.
Thus, a need exists for improved semiconductor structures.
While certain aspects of conventional technologies have been discussed to facilitate disclosure of the invention, Applicants in no way disclaim these technical aspects, and it is contemplated that the claimed invention may encompass one or more of the conventional technical aspects discussed herein.
In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was, at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.