Characterization of plasma etching induced interface states at Ti∕p-SiGe Schottky contacts

The authors have used current-voltage (I-V) data measured over a wide temperature range (100–300K) complemented by deep level transient spectroscopy (DLTS) for the assessment of the defects introduced in Si0.95Ge0.05 by argon plasma sputter etching. From DLTS, defect concentration depth profiling was extracted and revealed that the main defect introduced during argon plasma sputtering is located very close to the surface. I-V-T analysis shows that the electrical characteristics deviated from the ideal case and indicate the presence of interface states, resulting from the plasma etching induced surface states at Ti∕Si0.95Ge0.05 interface. The interface state density as well as its temperature dependence were obtained from forward bias I-V-T measurements by considering the bias dependence of effective barrier height Φe. It is found that interface states density is temperature dependent although weakly.