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

Abstract

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.

Characterization of physical and electrical properties of BaTiO3 films deposited on p-Si by modified polymeric precursors

“…It is found to be E g ϭ 3.95 eV in very good agreement with previously published results. 2,3,6,14,17 The magnitude of the leakage current varies from 10 Ϫ9 A to 10 Ϫ6 A, depending on the applied voltage.…”

“…8,17,18 In all cases, reliability issues have risen due to process related defects, leakage currents, or abnormal behavior of the dielectric. These issues have been reported and analysed concerning different materials and deposition techniques while recent reports indicate that degradation mechanisms need to be addressed in more detail if more complex systems are to be built.…”

“…The aim is to study the electrical properties, identify possible defects, and compare the results to those recently published on similar capacitors built with sputtered films deposited at low temperature. 17,20 Issues such as the leakage current and its origin, as well as the capacitive and conductive response of the MOSCAPs are examined. 21…”

Improvement of laser molecular beam epitaxy grown SrTiO3 thin film properties by temperature gradient modulation growth

“…Therefore, those STO films grown directly on Si were usually polycrystalline with randomly oriented grains. [4][5][6] Extensive research has been carried out on the finding of a solution to the problem. Up to know, the study mainly focuses on the introduction of additional materials, i.e., various single or double buffer layers between Typical work includes the growth of SrSi 2 submonolayer as a buffer layer by molecular beam epitaxy ͑MBE͒, which was reported by McKee et al 10 There are a few reports on the growth of STO directly on Si.…”

“…This is commonly found at the STO/Si interface grown by various techniques. [4][5][6]13,14 In order to examine behaviors of oxygen diffusion and amorphous layer in the STO/Si system, we have measured the changes in XPS core levels of Si 2p at the STO/Si interface grown within relatively low temperature ranges from 300 to 500°C. Figure 2 shows that a broad peak centered about 102.4 eV formed besides for the Si 2p peak from pure Si.…”