【作者】 牟宗信；

【导师】 李国卿；

【作者基本信息】 大连理工大学 ， 材料表面工程， 2006， 博士

【摘要】 非平衡磁控溅射沉积技术(Unbalanced Magnetron Sputtering,UMS)目前得到广泛关注,能够得到比较高的离子/原子到达比(Ion-to-atom Arrival Ratio,IAR),在相对较低的基体温度下沉积结构致密薄膜,通过磁场状态优化沉积参数。结构-区域模型(Structure-Zone-Model,SZM)包含沉积过程的关键因素,为确定非平衡磁控溅射沉积技术放电参数和沉积参数之间的关系,仍然需要深入研究其放电、沉积机制,通过建立精确的理论模型控制放电和沉积过程,以满足日益发展的应用需求。 溅射靶的磁场分布是非平衡磁控溅射系统的关键因素。通过增强溅射靶外侧的磁极形成非平衡的磁场分布,能够约束等离子体,增强电离;磁场梯度带来的磁镜效应增强电荷引出,系统的性能得到提高。本文使用的圆形平面磁控溅射靶内部磁极具有一定的非平衡度,构成永磁式非平衡磁控溅射靶(Permanent Magnet Unbalanced Magnetron Sputtering);通过附加一个同轴线圈加强系统的非平衡特征,形成同轴磁场约束非平衡磁控溅射靶(Coaxial Solenoid confining Unbalanced Magnetron sputtering)。本文通过这样两种相互对比的系统来研究同轴磁场变化对放电特性和沉积特性的影响。 采用Langmuir探针、发射探针、平面电极和发射光谱等方法研究了沉积区域的等离子体参数和同轴磁场(Coaixial Solenoid)对这些参数的影响规律。在同轴磁场作用下,其沉积区域电子温度、等离子体密度和离子饱和电流密度得到显著提高,有利于提高薄膜质量;沉积速率随溅射功率先增加,继续提高溅射功率,则沉积速率降低;由于电子受到磁场约束,沉积区域的等离子体电位降低;同轴磁场提高了系统的放电效率和低气压沉积过程的稳定性。采用圆形平面电极在轴向不同位置研究饱和离子电流(Saturation Ion Current)与同轴线圈电流、放电电流密度、空间位置之间的关系。实验结果表明同轴磁场显著影响收集电流密度通量,增强同轴磁场使饱和离子通量在距阴极200mm以上的位置达到9.5mA/cm~2,达到饱和值后保持稳定,不再受磁场和放电电流影响。 在系统的实验研究基础上,理论研究了同轴磁场对圆形平面磁控溅射系统放电特性和离子束流影响。根据蔡尔德定律研究了同轴磁场对于非平衡磁控溅射沉积系统伏安特性影响的基本规律。根据沉积过程中离子的分布特点,采用磁流体理论方法,建立反映更多还原

【Abstract】 The studies of unbalanced magnetron sputtering (UMS) has inspired great attention recently for highly ion bombardment, which can help to form higher ion-to-atom arrival ratio to deposit dense films with perfect quality. In UMS, the identification of relations between the discharge properties and deposition parameters becomes very difficult for multivariate process. The Structure-Zone-Model (SIM) includes basic parameters of film depostion. In order to model and control the discharge and deposition process the mechanism of the UMS need to be studied further to satisfy the increasing application.The magnetic field distribution is key to the properties of UMS. The unbalanced magnetron target is improved outside magnet pole, which form an unbalanced magnetic field to confine plasma, for a magnetic field gradient coming from a magnetic mirror effect.The circular plane magnetron target with a certain unbalanced degree is an Unbalanced Magnetron target in Permanent Magnet mode (PM-UMS). The system with improved unbalanced degree by additional coaxial solenoid is Coaxial Solenoid confinement Unbalanced Magnetron target (CS-UMS). The influence of the coaxial coil on the discharge and deposition properties of the unbalanced magnetron target has been studied. The parameters under the influences of different coil current, such as Paschen curves and voltage-current properties, electron temperature, plasma potential, deposition rate at the deposition position, were studied by Langmuir probe, emissive probe, planar electrode for measuring ion current and emissive spectroscopy methods. Under the influences of coaxial coil, electron temperature and the ion saturation current were increased. Coaxial magnetic field have reduced the discharge voltage on the cathode, improved the ionized efficiency and the stability of the deposition at a lower pressure.The electrode with a surface parallel to cathode measures ion flux at a bias voltage of -150V, a pressure of 0.2Pa, with argon discharge and different locations from cathode. The ion saturation current density is a function of the discharge current, coaxial coil current and substrate location. Under influence of the coaxial magnetic field the ion flux was increased froma negligible value to 9.5mA/cm2 at the location of more than 200mm from cathode, the results of experiment also show that ion flux incident to the substrate reaches saturation value and keep constant with variation of the discharge current and coil current The influence of coil on the voltage-current properties Was modeled based on Child law. By the magneto-hydrodynamic theory the ion flux as a function of discharge power, pressure and substrate location was modeled with magnetic mirror effect. The transportation of the ion and neutral particle were treated, respectively. As a result, the coaxial magnetic field improved the performance of the system. There is a fine consistency between the model and experiment results. The results can help to control the depositing parameter in quantity.By UMS, the smooth, dense and even TiNx film has been deposited at room temperature (RT). With variation of the coaxial magnetic field the incident ion-to-atom arrival ratio to the substrate (Ji/Jm ) have been studied at variation of sputtering power, bias and pressure, proportion of nitrogen-to-argon mass flow ratio (f(N2/Ar)) of depositing TiNx film. Atom force microscope (AFM) has been used to study surface roughness and the surface morphology of TiNx fihiL The structure of TiNx film was investigated by glancing angle incident X-ray diffraction method (G2XRD). The microhardometer and ball-on-disk friction was used to determine the influence on coefficient of static friction and the Knoop microhardness of deposition parameters of TiNx film. As a result, TiNx film at a bias of-50 V and with an ion-to-atom arrival ratio of 4.1 has the highest microhardness value with dense, small crystal island. f(N2 /Ar) in the range of 0.3-0.64 has better influence on the formation of deliver dense and smooth TiNx film morphology. At low temperature and low sputtering power the films trend to become deliver, dense structure with atom level smooth surface morphology. Applications of the parameter model can help to deposit film with ideal structure, performance and morphology.更多还原