Method of forming differential etch stop layer using directional plasma to activate surface on device structure

A method of semiconductor processing comprising:

• forming a differential etch stop layer having a first portion over an upper surface of a source/drain region and a second portion along a sidewall of a gate spacer, the source/drain region being in an active area, the gate spacer being over the active area proximate the source/drain region, a thickness of the first portion being greater than a thickness of the second portion, forming the differential etch stop layer comprising performing a directional;
• activation, wherein the forming the differential etch stop layer comprises using a first precursor of dichlorosilane and using a second precursor of ammonia;
• depositing an interlayer dielectric (ILD) over the differential etch stop layer;
• and
• forming a conductive feature through the ILD and the differential etch stop layer and contacting the source/drain region.

A method of semiconductor processing comprising:

• forming a contact opening extending through one or more dielectric layers, the contact opening exposing contact region of a substrate;
• forming a first monolayer on horizontal surfaces and vertical surfaces of the contact opening, the forming the first monolayer using a first precursor of dichlorosilane;
• performing a directional plasma process on the first monolayer to form an activated first monolayer, unactivated portions of the first monolayer remaining after the directional plasma process, the directional plasma process activating more of the horizontal surfaces of the first monolayer than vertical surfaces of the first monolayer;
• exposing the activated first monolayer and the unactivated portion of the first monolayer to a second precursor, the second precursor comprising ammonia, the second precursor reacting with the activated first monolayer at a faster rate than the second precursor reacts with the unactivated portions of the first monolayer;
• and
• repeating the forming the first monolayer, the performing the directional plasma process, and the exposing one or more times.