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This study compares the capacitance–voltage (C–V) characteristics in silicon–germanium (SiGe) metal-oxide-semiconductor capacitances with and without a silicon oxide capping layer. The SiGe channel with the silicon oxide capping layer exhibits an improved C–V property at room temperature but has an abnormal shift and depression at low temperature (77 K). We determined that the threshold voltage shift was induced by the Fermi-level when ambient temperature was changed. The additional silicon capping layer was responsible for introducing defects resulting in depression and hump in the C–V measurements. Such a phenomenon is mainly caused by the different distribution of defects, which was established by modifying the alternating current pulse amplitude during the C–V measurement. [ABSTRACT FROM AUTHOR]

HfZrOx (HZO)-based materials have received much attention due to their special film characteristics in recent years. Ferroelectric random access memory (FeRAM) based on this HZO material also has promising potential as a next generation memory due to its non-volatile characteristics, excellent endurance, and low power consumption. Previous research has mainly focused on the material properties of HZO-based FeRAM. However, an in-depth investigation of the electrical properties of HZO-based FeRAM is necessary to better understand its transporting mechanism. In this contribution, this study aims to investigate the mechanism of an HZO-based metal–ferroelectric-metal capacitor using comprehensive experimental results, including current–voltage, capacitance–voltage, and polarization–voltage measurements. Experiments at various temperatures are also conducted to help verify the transport mechanism. The low current transport by the Fowler–Nordheim tunneling mechanism does not change with temperature, whereas the high current transport via the Schottky mechanism increases with increasing temperature. We found that the orientation of the dipole plays an important role. Finally, we also propose a band model to explain the electron transport in this HZO-based FeRAM. [ABSTRACT FROM AUTHOR]