AN ATOM PROBE FIELD ION MICROSCOPY STUDY OF DISLOCATION-SOLUTE INTERACTIONS NEAR TWIN BOUNDARIES IN WEB SILICON

Atom probe field ion microscopy Is used to study dislocation-solute interactions near a twin interface in . .solar cells fabricated from dendritic web silicon.FIM specimens of web silicon containing a twin boundary in the apex region were prepared using a variety of techniques and analyzed in the atom probe.Results show that particles of Composition SiO, are found in the vicinity of twin boundaries in both high and low efficiency cell specimens.However, the particles are 1 nm -2nm in size in the high efficiency cell and 5nm -lOnm in the low efficiency cell specimens.It is proposed that small minority carrier lifetimes, responsible for the degradation of cell efficiency, are not due to bulk impurity effects but are linked to dislocations decorated with precipitates in the size range 5 -10 nm.