| AVS 55th International Symposium & Exhibition | |
| Applied Surface Science | Monday Sessions |
| Session AS-MoA |
| Session: | Electron Spectroscopies |
| Presenter: | M. Sawkar-Mathur, University of California, Los Angeles |
| Authors: | M. Sawkar-Mathur, University of California, Los Angeles C. Marchiori, IBM Zurich Research Laboratory J. Fompeyrine, IBM Zurich Research Laboratory J. Bargar, Stanford Synchrotron Radiation Laboratory M. Toney, Stanford Synchrotron Radiation Laboratory J.P. Chang, University of California, Los Angeles |
| Correspondent: | Click to Email |
Hafnium based amorphous oxides are currently being implemented to enable the 45-nm and 32-nm technology nodes of metal oxide semiconductor field effect transistors (MOSFETs). However, the interfacial issues arising at the amorphous oxide/crystalline Si interface justify the exploration of a lattice-matched crystalline oxide on Si to achieve an atomically sharp interface, thereby improving the device reliability. In this work, SrHfO3, a perovskite oxide, was grown on silicon using molecular beam epitaxy (MBE). In-depth structural analysis using synchrotron techniques including XRD with a four circle diffractometer and grazing incidence EXAFS was performed to determine the crystalline quality and short range chemical bonding and order in these ultra-thin SrHfO3 films. Nearly epitaxial growth of SrHfO3 on Si was observed with good crystalline quality and some misalignment of grains. From the in-plane diffraction pattern, the SrHfO3 (100) plane was found to be parallel to the Si(110) plane, yielding a 6% lattice mismatch. The d spacing of the SrHfO3 (300) plane was found to be 1.37 Å which corresponds well with the literature reported value of 1.36 Å, suggesting no significant strain in the film. Phi scans of the SrHfO3 (200) peak showed the four-fold symmetry expected for that plane, with no twinning, further substantiating the lack of significant strain in the film. The atomic planes were found to be highly parallel, as evidenced by the presence of interference fringes around the SrHfO3 (001) plane. Cluster models with a radial distance of 4 Å were constructed using the perovskite crystal structure of SrHfO3 to model the scattering amplitudes of the absorption spectra and quantify the nearest and second nearest neighbors surrounding the center absorbing Hf atom. A low level of disorder and minimal defects were observed. Based on the complementary analyses of synchrotron GI-EXAFS and XRD, MBE grown SrHfO3 on Si has the potential to be a crystalline metal oxide for implementation in CMOS devices.