Self-limiting liners for increasing contact trench volume in n-type and p-type transistors

A method of forming protective liners of semiconductor devices formed on a substrate, the method comprising:

• in an n-type region of the substrate, performing fabrication operations comprising:
• forming an n-type source or a drain (S/D) region;
• forming a first layer of protective material over a top surface of the n-type S/D region;
• forming a second layer of protective material over the first layer of protective material, wherein the second layer of protective material comprises an oxide of a first type of material;
• applying an anneal to:
• drive the first type of material into the first layer;
• drive a second type of material from the first layer into the second layer;
• and
• convert at least a first portion of the second layer of protective material to a first oxide of the second type of material, wherein the first oxide of the second type of material comprises a protective liner of the n-type S/D region;
• in a p-type region of the substrate, performing fabrication operations comprising:
• forming a p-type S/D region;
• forming the second layer of protective material over a top surface of the p-type S/D region, wherein the second layer of protective material comprises the oxide of the first type of material;
• applying the anneal to:
• drive the first type of material into the p-type S/D region;
• drive the second type of material from the p-type S/D region into the second layer;
• and
• convert at least a second portion of the second layer of protective material to a second oxide of the second type of material, wherein the second oxide of the second type of material comprises a protective liner of the p-type S/D region.

A set of semiconductor devices formed on a substrate, the devices comprising:

• an n-type region comprising:
• a first n-type source or a drain (S/D) region;
• a second n-type S/D region;
• a first layer of protective material over a top surface of the second n-type S/D region, wherein the first layer of protective material comprises a first type of material and a second type of material;
• and
• a second layer of protective material over the first layer of protective material, wherein the second layer of protective material comprises an oxide of the second type of material;
• a p-type region comprising:
• a first p-type S/D region;
• a second p-type S/D region;
• the second layer of protective material over a top surface of the second p-type S/D region, wherein the second p-type S/D region second layer of protective material comprises the first type of material and the second type of material, wherein the second layer of protective material comprises the oxide of the second type of material.