Methods of forming contact features in field-effect transistors

A method, comprising:

• providing a semiconductor structure having metal gate structures (MGs), gate spacers disposed on sidewalls of the MGs, and source/drain (S/D) features disposed adjacent to the gate spacers;
• recessing portions of the MGs;
• depositing a first dielectric layer over the recessed MGs, wherein the first dielectric layer is self-aligned with the gate spacers;
• forming S/D contacts (MDs) over the S/D features;
• recessing portions of the MDs;
• depositing a second dielectric layer over the recessed MDs and over the first dielectric layer;
• forming an interlayer dielectric (ILD) layer over the second dielectric layer;
• forming a trench in the ILD layer over the MGs;
• removing portions of the first dielectric layer exposed in the trench;
• depositing a metal layer over the MGs and the second dielectric layer;
• and
• planarizing a top surface of the metal layer to form conductive features over the MGs.

A method, comprising:

• forming a semiconductor structure having a gate stack (MG), a gate spacer disposed on a sidewall of the MG, and a source/drain (S/D) contact (MD) disposed over an S/D feature adjacent to the gate spacer;
• recessing portions of the MG;
• forming a first dielectric layer over the recessed MG;
• recessing portions of the MD;
• forming a second dielectric layer over the first dielectric layer, wherein portions of the second dielectric layer extend along a sidewall of the gate spacer to contact the recessed MD, and wherein the first and the second dielectric layers differ in composition;
• forming a patterned third dielectric layer to expose portions of the first and the second dielectric layers in a trench;
• selectively removing the exposed portions of the second dielectric layer with respect to the exposed portions of the first dielectric layer to expose the recessed MD in the trench;
• depositing a conductive layer in the trench;
• and
• planarizing the conductive layer to form a contact feature over the recessed MD, thereby removing the patterned third dielectric layer.