Methods of forming semiconductor devices with self-aligned contacts and low-k spacers and the resulting devices

A method, comprising:

• forming a sacrificial gate structure above a semiconducting substrate, said sacrificial gate structure comprising at least a sacrificial gate electrode that has a plurality of sidewalls;
• forming at least one sacrificial sidewall spacer on said sacrificial gate electrode;
• performing at least one etching process to remove at least a portion of said sacrificial sidewall spacer and thereby expose a portion of said sidewalls of said sacrificial gate electrode;
• after performing said etching process, forming a liner layer comprised of silicon nitride or silicon oxynitride on said exposed sidewalls of said sacrificial gate electrode;
• forming at least one layer of sacrificial gap fill material above said liner layer;
• performing at least one process operation to expose an upper surface of said sacrificial gate electrode;
• after exposing said upper surface of said sacrificial gate electrode, removing at least said sacrificial gate electrode to thereby define a gate cavity that is laterally defined by said liner layer;
• forming a replacement gate structure in said gate cavity;
• after forming said replacement gate structure, removing said at least one layer of sacrificial gap fill material;
• and
• forming a low-k sidewall spacer on said liner layer, wherein said low-k sidewall spacer is comprised of a material having a dielectric constant less than 7.