| Summary: | 碩士 === 國立中山大學 === 電機工程學系研究所 === 89 === ABSTRACT
In recent years, there has been increasing demands for high dielectric materials to replace SiO2 for high-density dynamic random access memories with ultra large scale integration (ULSI). As the dimensions of the charge storage node decrease in high-density dynamic random access memories (DRAMs), TiO2 and BaTiO3 are very promising candidates for applications with exhibiting higher dielectric constant, high refractive index and high chemical stability.
The physical and chemical properties of LPD thin film by means of several measuring instruments, including Fourier Transform Infrared Spectrometer (FTIR), Auger Electron Spectroscopy (AES), Secondary Ion Spectrometer (SIMS), and X-Ray Diffractometer (XRD). As for the category in the electrical properties, such as C-V curve and I-V curve, of LPD-BTO thin film is comprehended in the most important part of this chapter. Further, we try to improve these electrical properties of LPD-TiO2 and LPD-BTO thin film by post-annealing in oxygen atmosphere at several high temperatures.
From leakage current density-electric field intensity voltage (J-E) and capacitance-voltage (C-V) measurements, the leakage current densities are about (LPD-TiO2: 1 × 10-5 A/cm2 and LPD-BTO: 5 × 10-9 A/cm2). And the individual dielectric constants of both films (TiO2 and BTO) are calculated about 40 and 60. This value is larger than thermal oxide, PECVD oxide, and LPD-SiO2. We also can obtain the flat band voltage shifts of LPD-TiO2 and LPD-BTO films which are about –0.5V and 0V; the effective oxide charges which are calculated about –4.52×1011 cm-2 and –2.27×1012 cm-2
The future goals:
(1) Raising the atomic concentration of oxygen within both films and of barium within LPD-BTO film.
(2) Shortening the process in preparation of both deposition solutions.
(3) Re-checking both models.
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