Methods of forming source/drain regions using multilayer side wall spacers and structures so formed

摘要

Methods of forming a source/drain region can include the steps of forming a gate electrode on a substrate and forming a lightly doped source/drain region in the substrate self-aligned to the gate electrode. A first spacer can be formed on a side wall of the gate electrode. A second spacer can be formed on the first spacer on the side wall separate from the first spacer to provide a multilayer spacer on the side wall. A heavily doped source/drain region can be formed in the substrate self-aligned to the multilayer spacer. Related structures are also disclosed.