Electrical properties of SrTiO3 thin films on Si deposited by magnetron sputtering at low temperature

• Deposition of SrTiO3 (STO) thin films by radio-frequency magnetron sputtering in an ultrahigh vacuum system at a low substrate temperature (~200°C) was performed in order to produce high-quality STO/p-Si (100) interfaces and STO insulator layers with dielectric constants of high magnitude. The STO films were identified as polycrystalline by x-ray diffraction, and were approximated with a layered structure according to the best fitting results of raw data from both Rutherford backscattering spectroscopy and variable angle spectroscopic ellipsometry. Room-temperature current-voltage and capacitance-voltage (C-V) measurements on Al/STO/p-Si diodes clearly revealed metal-insulator-semiconductor behavior, and the STO/p-Si interface state densities were of the order of 1011 eV-1 cm-2. The dielectric constant of the STO film was 65, and the dielectric loss factor varied between 0.05 and 0.55 for a frequency range of 1 kHz-10 MHz. For a 387 nm thick STO film, the dielectric breakdown field was 0.31 MV cm-1, and the charge storage capacity was 2.1 µC cm-2. These results indicate that STO films are suitable for applications as insulator layers in dynamic random access memories or as cladding layers in electroluminescent devices. © 2001 American Institute of Physics.

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