Atomic Layer Doping for Future Si Based Devices

Abstract

The concept of atomic-level processing based on atomic-order surface reaction control is discussed. The main idea of the atomic layer approach is the control of the process by surface reactions at very low temperatures (even at room temperature). Results of B and P atomic layer doping of Si, Ge and SiGe are reviewed and discussed focussing on the control of the surface adsorption by changing temperatures and partial pressures of the dopant gases. 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{degree sign}C indicating preferred adsorption of B2H6 on Si and Ge sites and suppression of B cluster formation. In the case of B atomic layer doping of Si it is shown that the technique can be used for the selective deposition of polycrystalline Si. For P atomic layer doping of SiGe self-limitation of the process has been observed for temperatures between 200-550{degree sign}C allowing very precise dopant dose and location control.