The effect of laser thermal annealing (LTA) on delta-doped B has been investigated for the applications of super-steep-retrograde (SSR) 70 rim n-type metal-oxide-semiconductor field-effect transistors using undoped selective silicon epitaxy. Shallow (less than or equal to 50 Angstrom) melting by LTA was found to suppress the B loss, causing an anomalous lowering and fluctuation of threshold voltage (V-t), upon epitaxial channel growth and rapid thermal annealing (RTA). Under the laser fluence of 0.42 J/cm(2), the B profile was also observed to freeze without further diffusion upon RTA at 900 degreesC for 20 s. Significant B loss observed in conventional delta-doped SSR devices stemmed from the hydrogen ambient at 800 degreesC required for selective silicon epitaxy as well as the rapid B outdiffusion behavior. The laser-induced surface melting decreased the outdiffusion rate by increasing the portion of substitutional B, and also led to a surface roughening which made the B loss from the silicon surface difficult. As a result of LTA, much lower V-t fluctuation with reasonable V-t was obtained along with improved short channel characteristics. (C) 2003 American Vacuum Society.