Methods for fabricating semiconductor devices minimizing under-oxide regrowth

Methods for producing a semiconductor device are provided. In one embodiment, a method includes the steps of: (i) fabricating a partially-completed semiconductor device including a substrate, a source/drain region in the substrate, a gate stack overlaying the substrate, and a sidewall spacer adjacent the gate stack; (ii) utilizing an anisotropic etch to remove an upper portion of the sidewall spacer while leaving intact a lower portion of the sidewall spacer overlaying the substrate; (iii) implanting ions in the source/drain region; and (iv) annealing the semiconductor device to activate the implanted ions. The step of annealing is performed with the lower portion of the sidewall spacer intact to deter the ingress of oxygen into the substrate and minimize under-oxide regrowth proximate the gate stack.