Paper Title
Study of Liquid Phase Deposited HFO2/SI MOS Structure Prepared by Different Hydrochloric Acid Volumes

Abstract
With the development of the integrated circuits (IC), the SiO2 has reached the limits of its physical properties. Therefore, high-k gate oxide such as silicon nitride (Si3N4), aluminum oxide (Al2O3), yttrium oxide (Y2O3), titanium oxide (TiO2), zirconium oxide (ZrO2) and hafnium oxide (HfO2) is an attractive alternative for replacing the SiO2 in scaled MOSFET. Among them, HfO2 has many advantages such as high dielectric constant (≈ 25), large band gap (5.8 eV), high breakdown electric field (≈8.5 MV/cm) and thermal stability on silicon substrates. In this study, the Al/HfO2/p-Si metal-oxide-semiconductor (MOS) structure was fabricated by LPD. The growth solution is composed of 0.005 M Hf(SO4)2．4H2O and 0.3 M HCl solution and deposition time is kept at 5 hours. Electrical properties of HfO2 films were investigated with various HCl volumes (0, 15, 30 and 45 ml). From the experiment results, the optimal parameters were available at HCl volume of 15. The oxide capacitance (Cox), flatband voltage, k-value and effective oxide charge (QEFF) are 237.5 pF, -0.662 V, 24.3 and 3.1 ×1011 cm-2, respectively. The density of interface state (Dit) is 5.74 ×1011 cm-2eV-1. The flatband voltage offset of hysteresis loop is 0.027 V. The leakage current is 6.21 ×10-5 A/cm2 at -1 MV/cm. From this study, LPD-HfO2 can be successfully directly deposited on Si and have large potential to be used as gate oxide in the MOSFET in the future. Keywords - Liquid Phase Deposition, Hafnium Oxide, MOS, HfO2, Hydrochloric Acid.