Atomic-level processing based on surface reaction control is used for B and P doping during Si, SiGe or Ge epitaxy. The concept of atomic layer processing is base on the separation of adsorption of the dopant gases from the layer growth. By this way the doping process is controlled by surface adsorption Z desorption of dopant gas mainly. For B atomic layer doping of SiGe and pure Ge using B2H6, high doping levels and steep doping profiles have been reached. The process was found to be self-limited at ̃100°C indicating preferred adsorption of B2H6 on Si and Ge sites and suppression of B cluster formation. For P atomic layer doping on Si and SiGe self-limitation of the process has been observed for temperatures between 200-600°C allowing very precise dopant dose and location control.