Semiconductor device containing tubular liner spacer for lateral confinement of self-aligned silicide portions and methods of forming the same

A method of forming a semiconductor structure, comprising:

• forming a first active region in a substrate semiconductor layer located on or in a substrate, wherein the first active region has a doping of an opposite conductivity type than the substrate semiconductor layer;
• forming a contact-level dielectric layer above the substrate;
• forming a first contact via cavity extending into the first active region through the contact-level dielectric layer;
• forming a first tubular liner spacer at a periphery of the first contact via cavity;
• forming a first metal-semiconductor alloy portion on the first active region at a bottom region of the first contact via cavity by depositing a metal layer comprising a first elemental metal on the substrate semiconductor layer, and by inducing formation of a metal-semiconductor alloy material through reaction of the first metal with a semiconductor material in the first active region;
• removing unreacted portion of the metal layer selective to the first metal-semiconductor alloy portion from inside the first contact via cavity, whereby a top surface of the first metal-semiconductor alloy portion is physically exposed;
• forming a first metallic nitride liner comprising a metallic nitride material including nitrogen atoms and a second elemental metal different from the first elemental metal directly on the first tubular liner spacer and the first metal-semiconductor alloy portion;
• and
• forming a first metallic fill material portion in the first metallic nitride liner, wherein the first contact via cavity is filled with a first composite contact via structure including the first tubular liner spacer, the first metallic nitride liner, and the first metallic fill material portion.