IMPURITY DECORATION OF DEFECTS IN FLOAT ZONE AND POLYCRYSTALLINE SILICON VIA CHEMOMECHANICAL POLISHING

The behavior of impurities introduced in single and polycrystalline si licon via chemomechanical polishing was studied extensively. Using the electron beam induced current mode of a scanning electron microscope, chemomechanical polishing of boron-doped FZ silicon is shown to intro duce impurities which decorate and electrically activate swirl defects . Undecorated swirl defects do not behave as carrier recombination sit es. Chemomechanical polishing and preferential etching of boron-doped polycrystalline silicon produced etch pits which increased in concentr ation with decreasing resistivity, indicating an interaction between t he polishing impurity and boron. The impurity is shown to form discret e points of electrical activity homogeneously in a thin surface region of the material as well as increase the electron beam induced current contrast of dislocations and grain boundaries.