Resistivity and Hall Voltage Investigation of Phosphorus Segregation in Polycrystalline Si1-xGex Thin Films

ABSTRACTDopant segregation in atmospheric-pressure, chemically vapor deposited (APCVD), ~300 nm thick, polycrystalline Si0.95Ge0.5 and Si0.9Ge0.1 thin films, implanted at 80 KeV with 6×1013 to 5×1014 P/cm2 and annealed at 800 °C for 1 hr, was investigated using a combination of Hall and conductivity vs. temperature measurements. Hall measurements, feasible only in heavier doped films, showed that 29% of the phosphorus in Si0.9Ge0.1 and 42% of phosphorus in Si0.95Ge0.05 was electrically inactive. The loss was attributed to dopant segregating to grain boundaries. The density of grain boundaries states was also found to increase slightly with increasing Ge content, from 3.6×1012/cm2 in Si0.95Ge0.05 to 4.4×1012/cm2 in Si0.9Ge0.1.