Electrical properties of high-k ZrO2 gate dielectrics on strained Ge-rich layers

The electrical properties of ultrathin high-k ZrO₂ gate dielectric films deposited on strained Ge-rich layers using microwave plasma enhanced chemical vapor deposition (PECVD) technique at a low temperature (150°C) have been studied. The strained Ge-rich heterolayers have been analyzed by transmission: electron microscopy (TEM) and Raman spectra. X-ray photoelectron spectroscopy (XPS) has been used for analysis of chemical compositions of the deposited ZrO₂ films. The fixed oxide charge density (Q_p/q) and interface state density (D_it) are found to be 4.8 × 10¹¹ cm^-2 and 5.1 × 10¹⁰ eV^-1 cm^-2, respectively. The capacitance-voltage (C-V) characteristics and current-voltage (I-V) characteristics before and after constant current stressing exhibit good electrical properties and thus indicate the suitability of these films for future microelectronic applications.