Effect of Fluorine on the Dopant Diffusion of Through-Oxtoe Implanted Boron in Si - a Correlation with Microstructural Defects

Abstract

ABSTRACTIn case of boron through-oxide implant, it has been shown that the knocked-in oxygen atoms segregate at initially nucleated dislocation sites during the incubation and no significant junction movement is detected. The trapping of oxygen proceeds up to a certain time at which oxygen-precipitation occurs and this leads to an ejection of excess Si interstitials and further enhancing boron diffusion. However, with fluorine addition we believe that fluorine incorporation in SiO2 and/or SiO2/Si interface not only releases the strain gradient but also suppresses the silicon interstitials ejection and by this means suppresses the oxidation-enhanced boron diffusion. Correlated results of TEM microdefect structures and spreading resistance profiles are used to further support our postulation.