Silicided polysilicon spacer for enhanced contact area

A method to increase source/drain contact area of an integrated circuit transistor which is applicable to a silicon substrate having isolation structures, said method comprising:

• forming a gate structure on said silicon substrate having a gate conductor, shallow trench isolation structures, and ion implantations comprising the steps;
• forming a pad oxide layer on said silicon substrate;
• forming a pad nitride layer on said pad oxide layer;
• patterning said nitride layer to form a shallow trench isolation structure;
• stripping said nitride layer using a hot phosphoric acid process;
• performing an ion implantation process for a well and a voltage threshold region of said gate structure, wherein said gate structure is subjected to rapid thermal annealing after said ion implantation;
• stripping said pad oxide;
• forming a gate dielectric;
• depositing a gate polysilicon layer;
• planarizing and patterning said gate polysilicon layer;
• etching said gate polysilicon layer to form said gate conductor;
• forming extension ion implants extending from said gate conductor;
• depositing an etch-stop oxide layer;
• forming nitride spacers adjacent said gate conductor sides;
• forming conductive polysilicon spacers along side of said nitride spacers and adjacent each side of said gate conductor sides;
• performing a source/drain ion implantation process;
• shortening said conductive polysilicon spacers by etching such that at least one of said conductive polysilicon spacers is at a height less than a height of said adjacent gate conductor, wherein said height of said at least one conductive polysilicon spacer is thirty percent, fifty percent, or seventy percent of said gate conductor height
• performing an oxide etch to remove said etch-stop oxide layer and expose said gate conductor and said source/drain ion implantation regions;
• performing a selective epitaxial silicon deposition;
• and
• forming a conductive silicide on said exposed gate conductor, on said shortened conductive polysilicon spacers and on said exposed source/drain ion implantation regions to extend said source/drain contact area.