Transistor contacts and methods of forming the same

A method comprising:

• depositing an etch stop layer on a source/drain region;
• depositing an inter-layer dielectric on the etch stop layer;
• implanting an impurity in an upper region of the inter-layer dielectric, the upper region of the inter-layer dielectric having a greater concentration of the impurity than a lower region of the inter-layer dielectric;
• etching a contact opening in the inter-layer dielectric and the etch stop layer, the contact opening exposing the source/drain region, the contact opening having a straight sidewall in the lower region of the inter-layer dielectric, the contact opening having a rounded sidewall in the upper region of the inter-layer dielectric;
• and
• forming a source/drain contact in the contact opening, a top surface of the source/drain contact being coplanar with a top surface of the inter-layer dielectric.

A method comprising:

• forming a gate structure adjacent a gate spacer;
• forming a gate mask on the gate structure;
• implanting an impurity in the gate mask and the gate spacer, a concentration of the impurity in the gate mask decreasing in a direction extending from an upper region of the gate mask to a lower region of the gate mask, a concentration of the impurity in the gate spacer decreasing in a direction extending from an upper region of the gate spacer to a lower region of the gate spacer;
• and
• forming a contact extending through the gate mask to contact the gate structure.