Electrical properties of high-k ZrO/sub 2/ gate dielectrics on strained Ge-rich layers

The electrical properties of ultrathin high-k ZrO/sub 2/ gate dielectric films deposited on strained Ge-rich layers using microwave plasma enhanced chemical vapor deposition (PECVD) technique at a low temperature (150/spl deg/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 ZrO/sub 2/ films. The fixed oxide charge density (Q/sub p//q) and interface state density (D/sub it/) are found to be 4.8 /spl times/ 10/sup 11/ cm/sup -2/ and 5.1 /spl times/ 10/sup 10/ eV/sup -1/ cm/sup -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.