溅射功率和气压对直流磁控溅射制备钨薄膜的影响

The influence of sputtering power and gas pressure on the preparation of tungsten films by DC magnetron sputtering

摘要:

钨薄膜具有高熔点、高导电性、优异的耐化学腐蚀性和强抗辐照性等特性,广泛的应用于微电子、核能工程等领域。由于薄膜的结构和性能对沉积参数具有很强的依赖性,因此控制沉积过程的工艺参数对获得优异性能的钨薄膜至关重要。采用DC磁控溅射技术在硅衬底上制备钨薄膜,探究了溅射功率和气压对钨薄膜沉积速率、电阻率和相结构的影响。采用原子力显微镜、XRD、轮廓仪、四探针电阻测量表征了薄膜的微观结构和电学性能。结果表明,薄膜的沉积速率受溅射功率和气压共同影响,随功率的增加呈线性增加,随溅射气压的增加先达到峰值,然后下降。薄膜的电阻率和表面粗糙度的大小依赖于溅射气压,且随溅射气压的增加而增加,薄膜电阻率的增加可能是由于表面粗糙度的增加导致的。在恒定的溅射功率下,β-W的形成主要取决于溅射气压,几乎所有β-W相都在高溅射气压下形成,然而,当溅射功率足够大,在较高的气压下也会观察到部分α-W相的形成。钨薄膜中特定相结构(α-W/β-W)的形成,不仅取决于沉积气压,还与溅射功率相关,归根可能与入射到基片的原子能量相关。

Abstract:

Tungsten films have excellent characteristics such as high melting point, high conductivity，stable chemical properties, and strong radiation resistance, and are widely used in microelectronics, nuclear energy engineering and other fields. Since the structure and performance of the film have a strong dependence on the deposition parameters, it is essential to control the process parameters of the deposition process to obtain a tungsten film with excellent properties. This paper studies the effects of sputtering power and sputtering pressure on the deposition rate, microstructure, and phase structure of tungsten films. Using DC magnetron sputtering technology, a tungsten film is prepared on a Si substrate at room temperature. Atomic force microscope, XRD, four-probe resistance measurement, profiler, etc. were used to characterize the structure and electrical properties of the film. The results show that the deposition rate of the film is affected by the sputtering power and the gas pressure. The deposition rate increases linearly with the increase of the power, and first increases to a peak and then decreases with the increase of the gas pressure. The resistivity and surface roughness of the film depend on the sputtering pressure, and increase with the increase of the sputtering pressure. The increase in the resistivity of the film may be caused by the increase in the surface roughness. Under constant sputtering power, the formation of α-W mainly depends on the sputtering gas pressure. All β-W phases are formed under high pressure, but for the sputtering power is large enough, under higher pressure, the formation of some α-W phases will also be observed. The formation of the specific phase structure (α-W/β-W) in the tungsten film is not only dependent on the deposition pressure, but also related to the sputtering power, which may be related to the energy of the atoms incident on the substrate.