Methods of forming mis contact structures on transistor devices

A method of forming an MIS contact structure on a transistor, comprising:

• forming a contact opening in at least one layer of insulating material, said contact opening exposing an upper surface portion of a source/drain (S/D) region of said transistor that is doped with a source/drain (S/D) dopant ion;
• performing a plurality of conformal deposition processes to conformally deposit first, second and third layers of material within said contact opening wherein performing said plurality of conformal deposition processes comprises:
• performing a first conformal deposition process to conformally deposit said first layer within said opening, wherein said first layer comprises one of zirconium oxide or hafnium oxide, is positioned on and in direct contact with said exposed upper surface portion of said S/D region, and covers an entirety of sidewall surfaces of said contact opening;
• performing a second conformal deposition process to conformally deposit said second layer within said opening, wherein said second layer comprises a metal-containing material and is positioned on and in contact with said first layer;
• and
• performing a third conformal deposition process to conformally deposit said third layer within said opening, wherein said third layer comprises a conductive cap material and is positioned above said second layer;
• performing a contact ion implantation process to form a contact ion implant region comprising a contact ion that is positioned at least partially in at least one of said first, second or third layers of material, wherein said contact ion comprises an ion that is different than said S/D dopant ion;
• forming a fourth layer of material comprising a conductive material above said third layer such that said fourth layer overfills said contact opening;
• and
• performing at least one process operation to remove portions of said first, second, third and fourth layers of material positioned outside of said contact opening.