The Nano-Cu₃N And PLZT Thin Films Deposited By Radio-frequency Magnetron Sputtering Method

In recent years, copper nitride (CU3N) thin films attracted more attentions and were investigated intensively because of its' distinct structure and lower thermal-decomposition temperature, Cu₃N has potential applications in many fields such as optical storage, micro-electronic device, magnetic and so on. The series of Cu₃N films were prepared on glass substrate using radio frequency magnetron sputtering method via changing the sputtering ambient, deposition distance, radio frequency power or substrate temperature. The films were characterized by X-ray diffraction (XRD), UV-visible spectrum, four-point probe, atomic force microscope (AFM) and field emission scanning electron microscope (FE-SEM) methods. And chemical states of the elements of the films were studied by X-Ray photoelectron spectroscopy (XPS).In pure nitrogen ambient and the substrate temperature was 150℃, as-deposited samples which were grown along (100) direction had more N content relatively, extra N content distributed in grain boundaries and they were amorphous;perhaps the N atoms inserted in the body centre of the cell lattice, the lattice constants increased as the total flux. All the films were insulators, and lattice constant were lower than the critical lattice constant 3.868 A. There were no Cu atoms inserted in the lattice interstitial site. When introducing the sputtering gas argon and decreasing the total flux, the (111) peak appeared at high nitrogen partial pressure.Deposition distance has some extent influence on preparing Cu₃N films. When deposition distance was larger than 40mm in pure nitrogen ambient, the films deposited on glass substrate not heated on purpose were amorphous. But decreasing to 35mm, the films crystallized well were obtained. In argon and nitrogen mixture sputtering gas, the films deposited at large deposited distance were insulators;on the contrary, the films might be semiconductors. It was dependent on the ratio of argon and the substrate temperature, the orders of the electric resistivity was ranged from 10¹ to 10³ Ω·cm.On the whole, the lattice constant of the films deposited in pure nitrogen ambient were small, but when introducing Ar gas, the lattice constant became large. Due to peening effect, some Cu atoms were knocked in lattice interstitial side or grain boundaries by high-energy Ar ions. This leads to the expansion of the lattice. And the Cu atoms in thebody centre as the donors have the contributions to the conductivity. Additionally, the lattice constant decreased with elevating the substrate temperature, it is demonstrated that the amount of Cu atoms inserted decreased. The lattice constant of the films was largest when the substrate was not heated.When admitting the hydrogen gas, we find that the H elements could be inserted in the lattice cell easily. And the influence on modifying the conductivity and optical gap was remarkable. The resistivity and optical gap were decreasing as the hydrogen flux increasing. The optical gap was lower than leV, to some extent, it shows metallic behavior. But the films doped with Ti Atoms, the lattice constant did not change obviously, and they were insulators. We assume that the Ti atoms did not insert in the body centre, therefore, no influence on conductivity were observed in our experiment. In addition, the electrical resistivity of Ni doped CU3N was changing evidently, but the optical gap maintained at -leV which did not gain the modification. The films were semiconductors. By analyzing the lattice constant and conductivity, we can conclude that the Ni atoms were inserted in the body centre of the lattice cell. The Ni atoms as donors modified the conductivity obviously.CU3N film elements were studied by XPS, which indicated that electron binding energy of doped CU3N films was in the rang of 397.7 -397.9eV, Cujp^a electron binding energy was in the rang of 932.3-933.leV;which indicated that H doped CU3N films of electron binding energy was in the rang of 397.7-399.leV, Cu2P3/2 electron binding energy was in the rang of 932.8-933.leV .The indirect optical binding energy of undoped insulated CU3N films was in the rang of 1.5¹.7eV, indirect optical binding energy of undoped semiconductor CU3N films was in the rang of 1.2¹.5eV. Decomposed temperature of undoped CU3N films was about at 300°C, H doped CU3N films were decomposed initially at 150°C and completely at 250 °C.Ferroelectrical storage materials have been studied widely for their non-volatile, rapid storage speed and abroad application areas. At present, the ferroelectrical materials with lead have the best ferroelectrical properties. The (Pbx,Lai.x)(Zry,Tiz)O3 (i.e PLZT) thin films were deposited on ITO/glass substrates by rf magnetron sputtering method and the substrates were not heated deliberately. Then the as-deposited PLZT thin films were heat-treated covered with PbO powder and the films crystallized to perovskite structure. The pyrochlor is the transition phase before the perovskite PLZT formed.The formation of pyrochlor phase is mainly because of lead insufficiency. The leadlost so serious when heat-treated above 600 degrees that the perovskite PLZT can't formed when heat-treated in air atmosphere. Covered with PbO powder in the heat-treatment process could prevent the lead lost effectively and the lead oxide diffused into the film to supplement the insufficient lead at the same time. The lead would be excessive when heat-treated covered with PbO powder and the excessive lead existed in grain boundary and interface in the form of PbO, decreaced the crystallized energy and the perovskite PLZT thin films forms at relatively lower heat-treatment temperature (600 degrees).