Semiconductor device and method of fabricating the same

A semiconductor device, comprising:

• a semiconductor substrate;
• a gate stack on the semiconductor substrate;
• an air spacer around the gate stack;
• a first spacer around the air spacer;
• a second spacer on the air spacer and the first spacer;
• a third spacer between the gate stack and the air spacer;
• and
• a first sacrificial layer on the gate stack, wherein the third spacer extends along a sidewall of the first sacrificial layer.

A method of fabricating a semiconductor device, comprising:

• forming an interlayer dielectric layer and a gate stack on a semiconductor substrate;
• forming an air spacer and a first spacer surrounding a sidewall of the gate stack, wherein the first spacer is on a sidewall of the interlayer dielectric layer, and the air spacer is between the gate stack and the first spacer;
• forming a second spacer on the first spacer and the air spacer, wherein the second spacer has a portion in contact with a sidewall of the first spacer;
• forming a first contact hole landing on the second spacer and the gate stack, wherein a sidewall of the first contact hole is defined by the second spacer;
• and
• filling the first contact hole with a conductive material.