HiPIMS-CVD Hybrid Process for Advanced Functional Coatings: Proof of concept

磁控溅射是一种物理气相沉积(PVD)工艺，在工业上广泛用于沉积多种用途的功能涂层。虽然该工艺能够在复杂的多层堆栈中大面积沉积各种功能材料，包括许多氧化物、氮化物和金属，但沉积速度相对较低，使得某些材料或产品的沉积不经济。此外，仍有一些具有重要商业价值的材料，如氧化铝，会导致严重的加工不稳定性(如起弧、阳极表面损失、产生负离子等)，这限制了它们的使用。等离子体增强化学气相沉积(PECVD)是一种竞争过程，在该过程中，气体前体通过等离子体中的高能粒子驱动的反应在衬底上形成固体沉积。PECVD工艺通常具有沉积速率高、一致性高和粗糙度低的优点，但在材料范围和可沉积堆叠的复杂性方面受到限制，主要受可用前驱体的限制。为了降低产品成本和改善性能，需要提高溅射过程的速率和稳定性，以及类似地需要改善/扩大PECVD过程的材料选择和均匀性，以开辟新的应用。实现这些目标的另一种方法是同时结合这些技术。因此，这个学术/工业合作项目旨在开发新的混合沉积工艺，将最新的磁控溅射技术与PECVD技术相结合，以高速沉积增强型功能薄膜，这些增强功能薄膜能够扩大规模并集成到现有的大面积在线沉积设备中，以提供一种新的改进的生产路线，最好是在低温下。这里采用的创新方法将是使用HiPIMS(高功率脉冲磁控溅射)功率输送模式来驱动磁控管和CVD工艺。这是HiPIMS第一次在这种环境中使用，该提案旨在作为一个“概念验证”项目。HIPIMS涉及在磁控溅射阴极上短时间内施加非常大的功率脉冲。这些强烈的脉冲产生了高密度的等离子体，导致了溅射物种的高度电离。然后，可以通过改变磁控管的磁场强度来控制涂层材料到衬底的通量。因此，磁阵列的调整允许控制溅射金属掺杂到生长的CVD膜的通量，同时仍然在相同的压力和时间平均功率下操作，因此仍然在工艺区中保持相同的等离子体密度。因此，该项目的主要成果将是开发一种新的合成功能薄膜的方法。这种方法将通过精心挑选的与工业相关的功能薄膜的沉积和沉积过程的表征来验证。

Magnetron sputtering is a physical vapour deposition (PVD) process extensively used in industry for the deposition of functional coatings for many applications. Although the process is able to deposit a wide range of functional materials including many oxides, nitrides and metals in complex multi-layer stacks with exceptional uniformity over large areas, deposition rates are relatively low, making the deposition of certain materials or products uneconomical. In addition, there are still some commercially important materials, such as aluminium oxide, which can cause severe processing instabilities (i.e. arcing, loss of anode surfaces, creation of negative ions, etc.), which restricts their usage. Plasma enhanced chemical vapour deposition (PECVD) is a competing process in which gaseous precursors form solid deposits on the substrate through reactions driven by energetic particles from the plasma. PECVD processes generally have the advantage of very high deposition rates, high conformity and low roughness, but are limited, largely by the available precursors, in the range of materials and complexity of the stacks that can be deposited. There are also limitations in uniformity over large area substrates.In order to reduce product cost and improve performance, there is a demand to improve upon the rate and, where applicable, the stability of the sputtering process and a similar demand for improving/expanding the material choice and uniformity of the PECVD process to open up new applications. An alternative means of achieving these goals is to combine the technologies simultaneously. This academic/industrial collaborative project is designed, therefore, to develop new hybrid deposition processes, combining the latest magnetron sputtering technologies with PECVD technologies for the high rate deposition of enhanced functional films, which are capable of scale-up and integration into existing large area inline deposition facilities to provide a new improved route to production, ideally at low temperature. The innovative approach taken here will be to use the HiPIMS (high power impulse magnetron sputtering) power delivery mode to drive both the magnetron and the CVD process. This is the first time that HiPIMS will have been used in this environment and this proposal is designed to act as a 'proof of concept' project. HIPIMS involves the application of very large power pulses to magnetron sputter cathodes for short periods. These intense pulses create high plasma densities, leading to a high degree of ionization of the sputtered species. The flux of coating material to the substrate can then be controlled by varying the magnetic field strength of the magnetron. Thus, adjustment of the magnetic array allows a means of controlling the flux of sputtered metal dopant to the growing CVD film, whilst still operating at the same pressure and time averaged power and, therefore, still maintaining the same plasma density in the process zone. The primary deliverable from this project will, therefore, be the development of a new method for the synthesis of functional films. This method will be validated through the deposition of carefully selected functional films relevant to industry and the characterisation of the deposition process.