ECLIPSE: Multiscale Modeling of Crossed-Field Discharges with Speed-Limited Particle-in-Cell Simulation

该项目旨在开发和演示优化等离子体磁控溅射的计算机模拟技术。磁控溅射用于生产对包括集成电路和太阳能电池在内的许多重要产品至关重要的薄层。磁控溅射设备通过使用高能离子将原子从阴极材料上敲击/溅射到基片上，从而在基片材料上涂覆一层。改进这些设备将带来更可靠、更高质量的涂层、更低的生产成本和更高的性能--更便宜、更快的电子产品和更高效的太阳能电池板。改进的关键是控制溅射原子，这需要控制离子的密度、能量和分布。该项目实现的计算机模拟将允许调查几乎无法通过实验获得的系统细节，以及更快地探索清洁能源技术的设计变化。因此，该项目得到了等离子体科学与工程领先创新生态系统(ECLIPSE)计划的支持。阴极轰击离子在由放电产生的等离子体中加速；磁场减少电子损失以维持等离子体。等离子体很难建模：它是一个非平衡的、部分电离的、中等碰撞的、具有多个离子物种和等离子体-表面相互作用的复杂几何结构的腔室。细胞内粒子(PIC)计算机模拟具有模拟所有这些效应的能力。然而，巨大的计算成本对设计优化提出了严峻的挑战，这需要大量的仿真来探索广泛的条件。在这个项目中，将开发和测试多种等离子体建模技术来加速磁控溅射的PIC模拟，包括非均匀网格间距、允许网格单元大于等离子体德拜长度的节能PIC算法以及速度限制的PIC算法，该算法减少了完成模拟所需的时间步数。这些技术预计在一起使用时将特别有效，它们将适用于磁控溅射以外的广泛低温等离子体模拟。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project aims to develop and demonstrate computer simulation techniques for optimizing plasma-based magnetron sputtering. Magnetron sputtering is used to produce thin coatings essential to many important products, including integrated circuits and solar cells. Magnetron sputtering devices coat a substrate material by using energetic ions to knock/sputter atoms off the cathode material and onto the substrate. Improving these devices will lead to more reliable, higher quality coatings, lower production costs, and increased performance - cheaper, faster electronics and more efficient solar panels. The key to improvement is controlling the sputtered atoms, which requires controlling the density, energy, and distribution of ions. Computer simulations enabled by this project will allow investigation of system details that are all but inaccessible via experiment, as well as faster exploration of design changes for clean energy technologies. As such, this project is being supported under the ECosystem for Leading Innovation in Plasma Science and Engineering (ECLIPSE) program.The cathode-bombarding ions are accelerated within a plasma produced by an electric discharge; a magnetic field reduces electron loss to maintain the plasma. The plasma is difficult to model: it is non-equilibrium, partially ionized, moderately collisional, with multiple ion species and plasma-surface interactions in a chamber with complicated geometry. Particle-in-cell (PIC) computer simulation has the power to simulate all these effects. However, the large computational cost poses severe challenges for design optimization, which requires many simulations to explore a wide range of conditions. In this project multiple plasma modeling techniques will be developed and tested to speed-up PIC simulation of magnetron sputtering, including non-uniform grid spacing, energy-conserving PIC algorithms that allow grid cells larger than the plasma Debye length, and the speed-limited PIC algorithm, which reduces the number of time steps needed to complete a simulation. These techniques are expected to be especially effective when used together, and they will be applicable to a wide range of low-temperature plasma simulations beyond magnetron sputtering.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.