Effect of Ge Surface Nitridation on the MOS Devices

In this paper, the effect of Ge surface nitridation on Ge/HfO₂/Al MOS capacitors has been studied. Low-frequency measurements indicated the presence of significant interface states in surface nitrided devices. As temperature decreased from 300 to 140 K, electron trapping increased monotonically in both nitrided and nonnitrided devices, but the interface state density didn´t show a major fluctuation in nitrided devices as compared to nonnitrided devices. A constant voltage stress was applied on both samples to test their behavior under stress. Electron trapping was dominant in nonnitrided devices at lower stress voltages. After relaxation, detrapping was observed as devices recovered to their original state. Nitrided devices showed hole trapping after stress, but further device deterioration was observed after relaxation