Simulation of Rapid Thermal Annealed Boron Ultra-Shallow Junctions in Inert and Oxidizing Ambient

Abstract

ABSTRACTRapid Thermal Annealing (RTA) is indispensable for the formation of ultra-shallow source/drain junctions. To improve the annealing conditions, a fundamental understanding of the influences on the diffusion/activation process is necessary. Ion implantations of 1 keV boron at a dose of Φ≈1 I.1015 cm-2 are annealed in a SHS2800E RTP-system under controlled concentrations of oxygen in nitrogen ambient (0-1 ppm up to 1%). Concentration-depth profiles, measured by Secondary Ion Mass Spectroscopy (SIMS), are simulated within the framework of the kickout model involving diffusion enhancement via supersaturation of silicon self-interstitials. The validity of this interpretation is supported by the simulated results which are in good agreement with expenimental data. After RTA for 10 s at 1050°C the junctions are varying within a range of 800Å to 1400Ådepending on the annealing ambient. The results of the simulation yield finite values of self-interstitial supersaturation as a function of the oxygen concentration.