Electrical characterization and annealing behavior of defect introduced in Si during sputter etching in an Ar plasma

Abstract

We have employed current–voltage and capacitance–voltage measurements in conjunction with deep level transient spectroscopy to characterize the defects induced in n-Si during rf sputter etching in an Ar plasma. The reverse current, at a bias of 1 V, of the Schottky barrier diodes fabricated on the etched samples decreased nonmonotonically with etch time to a minimum at 6 min and, thereafter, increased. The reverse current also increased with decreasing plasma pressure. The barrier heights of the diodes followed the opposite trend. Six prominent electron traps were introduced in the substrate during Ar sputter etching. A comparison with the defects induced during high-energy alpha-particle and electron irradiation of the same material revealed that sputter etching created the VO and VP centers and V2−/0. The V2=/− charge state of the divacancy was not detected in our plasma etched samples. We have attributed the nondetection of V2=/− to the presence of defect-induced stress fields in the etched samples. A secondary defect with an energy level at Ec−0.219 eV was introduced during annealing and was found to be stable at 650 °C. This defect was introduced at the expense of a sputter-etching induced defect P4, which has similar electronic and annealing properties as EAr201 (Ec−0.201 eV), created in Ar-ion bombarded n-type Si.