Low-k gate spacer and formation thereof

A method of forming a semiconductor device, the method comprising:

• forming a fin protruding from a substrate, the fin comprising a semiconductor material;
• forming first spacers over the fin, wherein the first spacers form a recess between the first spacers, the first spacers comprising a dielectric material;
• terminating a surface of the fin between the first spacers with hydroxyl groups;
• selectively forming a self-aligned monolayer on the surface of the fin, the self-aligned monolayer not extending from a top surface of the fin to a top surface of the first spacers;
• selectively forming second spacers along sidewalls of the first spacers in the recess, the self-aligned monolayer preventing the second spacers from covering the self-aligned monolayer along a bottom of the recess;
• removing at least a first portion of the self-aligned monolayer to expose the fin;
• forming a gate dielectric over the fin and sidewalls of the second spacers;
• and
• forming a gate electrode over the gate dielectric.

A method of forming a semiconductor device, the method comprising:

• forming a first dielectric layer over a semiconductor fin;
• terminating a first surface of the first dielectric layer and a second surface of the semiconductor fin with a first species;
• performing an etching process, wherein the etching process removes the first species on the first surface of the first dielectric layer, wherein the first species remains on the second surface;
• performing a silylation process to form an inhibitor layer, wherein the silylation process reacts with the first species on the second surface, the silylation process not reacting with the first surface of the first dielectric layer;
• and
• depositing a second dielectric layer on the first dielectric layer, depositing the second dielectric layer comprises introducing a first gas, the first gas reacting with the first surface but not the inhibitor layer.