Arsenic-doped source/drain with phosphorus-doped contact region for dopant diffusion control

An electronic device, comprising:

• one or more transistors, wherein the respective transistors comprise:
• a plurality of source or drain structures, wherein the respective source or drain structures comprise a first region and a second region, wherein the first region comprises silicon doped with arsenic, wherein the second region comprises silicon doped with phosphorus, and wherein the second region is adjacent to a contact interface between the respective source or drain structures and respective conductive contacts of a plurality of conductive contacts;
• and
• the plurality of conductive contacts, wherein the respective conductive contacts comprise metal, and wherein the respective conductive contacts are coupled to the second region of the respective source or drain structures at the contact interface.

A method, comprising:

• forming a plurality of epitaxial structures, wherein the respective epitaxial structures comprise silicon doped with arsenic;
• forming a channel between the epitaxial structures, wherein the channel comprises silicon;
• forming a gate over the channel;
• forming a plurality of implants in the epitaxial structures or forming a plurality of epitaxial layers over the epitaxial structures, wherein the respective implants comprise phosphorous or the respective epitaxial layers comprise silicon doped with phosphorous;
• and
• forming a plurality of conductive contacts, wherein the respective conductive contacts are coupled to the respective epitaxial structures or the respective epitaxial layers.