Low-resistance and thermally stable contacts with phosphide or arsenide metal compound layers

Abstract

Contacts to n-type source/drain regions comprise a phosphide or arsenide metal compound layer. The phosphide or arsenide metal compound layers can aid in forming thermally stable low resistance contacts. A phosphide or arsenide metal compound layer is positioned between the source/drain region and the contact metal layer of the contact. A phosphide or arsenic metal compound layer can be used in contacts contacting n-type source/drain regions comprising phosphorous or arsenic as the primary dopant, respectively. The phosphide or arsenide metal compound layers prevent diffusion of phosphorous or arsenic from the source/drain region into the metal contact layer and dopant deactivation in the source/drain region due to annealing and other high-temperature processing steps that occur after contact formation. Phosphide and arsenide metal contact layers can also reduce the amount of silicide that forms in source/drain regions during processing by limiting the amount of contact metal that diffuses into source/drain regions.