Silicide protection during contact metallization and resulting semiconductor structures

摘要

A semiconductor transistor has a structure including a semiconductor substrate, a source region, a drain region and a channel region in between the source region and the drain region. A metal gate, having a top conductive portion of tungsten is provided above the channel region. A first silicon nitride protective layer over the source region and the drain region and a second silicon nitride protective layer over the gate region are provided. The first silicon nitride protective layer and the second silicon nitride protective layer are configured to allow punch-through of the first silicon nitride protective layer while preventing etching through the second silicon nitride protective layer. Source and drain silicide is protected by avoiding fully etching a gate opening unless either the etching used would not harm the silicide, or the silicide and source and drain contacts are created prior to fully etching an opening to the gate for a gate contact.

主权项

1. A transistor, comprising;
a semiconductor substrate; a source region, a drain region and a channel region therebetween; a metal gate above the channel region, at least a top conductive portion of the metal gate comprising tungsten; openings through at least one layer of one or more materials to the source region, drain region and gate; a tungsten contact filling the gate opening, wherein the gate contact is in direct contact with the top conductive portion of the gate; silicide for the source and drain regions; a liner lining only a portion that is less than all of the inner surfaces of the source and drain openings; and tungsten contacts filling the partially lined source and drain openings.