DELTA-DOPING IN SI AND SIGE BY LP(RT)CVD

Sharp profiles of boron were prepared by Low Pressure (Rapid Thermal) Chemical Vapor Deposition (LP(RT)CVD). Two different approaches for th e delta doping were used. In the first case the dopants were incorpora ted into the growing film. The process was kinetically controlled. By this way B-delta-layers with a steepness of 1.7 nm/decade were measure d by Secondary ion mass spectrometry (SIMS) for the profiles prepared. In the second case the doping was performed during an interruption of layer growth. The process was controlled by the surface adsorption eq uilibrium of dopants. Using this regime B-delta-layers of 1 monolayer and with a steepness of 1.4 nm/decade were obtained in SiGe. The value s of the estimated steepness represent an extremely sharp profile for a CVD process. Structural properties of the delta-doped layers were in vestigated using cross sectional transmission electron microscopy (XTE M). The steepness estimated by SIMS was compared with high depth resol ution spreading resistance (SR) measurements which detect the electric al active boron only.