Metal Complexes for Preparing Ferroelectric Thin Films by Metalorganic Chemical Vapor Deposition

Abstract

Magnetohydrodynamic equilibrium configurations with hollow current density profiles in the HL-2A tokamak are reconstructed for pellet injection discharges. The experimental data of pressure profiles, resulting from electron temperature measurements and a model density profile, analogous to that measured in the JET experiment, and Mirnov pickup coil signals are employed in the reconstructions. It is explicitly shown for the first time that configurations with hollow current density profiles may be realized by multiple pellet injection in HL-2A tokamak experiments. The reconstructed results show there exists a negative magnetic shear region in the plasma core which would benefit confinement improvement.

Volatile Lead β-Diketonates as CVD Precursors

“…A more detailed description has already been published. [14] As can be seen from Table 3, the thermal stability of Pb(pta) 2 vapor is higher than that of Pb(dpm) 2 . In the presence of oxygen, the thermal stability of the studied complexes decreases.…”

“…Attempts are being made to use volatile β-diketonate complexes. [1][2][3][4] However, thermal properties of lead β-diketonates as CVD precursors have not yet been studied systematically.…”

“…An ampoule filled with sample and placed in the evaporator was heated up to a certain temperature. The evaporator temperature was 125°C for Pb(dpm) 2 and 153°C for Pb(pta) 2 . The vapor of the precursor was transferred to the thermal reactor via a heated pipeline.…”

“…At temperatures higher than 450°C the intensity of the "metal-containing peaks" is close to zero, which indicates practically complete decomposition of molecules arriving in the reactor. The experimental data for the thermal decomposition of Pb(pta) 2 are presented in Figure 6. A more detailed description has already been published.…”

Kinetic Study of the Metalorganic Chemical Vapor Deposition of PbTiO3 Films from Pb(C2H5)4/Ti(i-OC3H7)4/O2 Reaction System

“…8) Chelate precursors like metal dipivaloylmethanoto (DPM) compounds have also been applied as CVD gas sources for ferroelectric thin films. [9][10][11] The alkyls and alkoxides have the advantage of high vapor pressures at normal temperature over the DPM compounds despite of their stronger poisonous property. One of the commonly used precursor system for preparation of PbTiO 3 films is the reaction of tetraethyl lead [Pb(C 2 H 5 ) 4 ] and titanium tetraisopropoxide [Ti(i-OC 3 H 7 ) 4 ] in the presence of oxygen.…”