Charges injection and retention in thin dielectric layers remain critical issues due to the great number of failure mechanisms they inflict. Achieving a better understanding and control of charge injection, trapping and transport phenomena in thin dielectric films is of high priority aiming at increasing lifetime and improving reliability of dielectric parts in electronic and electrical devices. Thermal silica is an excellent dielectric but for many of the current technological developments more flexible processes are required for synthesizing high quality dielectric materials such as amorphous silicon oxynitride layers using plasma methods. In this article, the studied dielectric layers are plasma deposited SiOxNy. Independently on the layer thickness, they are structurally identical: optically transparent, having the same refractive index, equal to the one of thermal silica. Influence of the dielectric film thickness on charging phenomena in such layers is investigated at nanoscale using Kelvin Probe Force Microscopy (KPFM) and Conductive Atomic Force Microscopy (C-AFM). The main effect of the dielectric film thickness variation concerns the charge flow in the layer during the charges injection step. According to the SiOxNy layer thickness two distinct trends of the measured surface potential and current are found, thus defining ultrathin (up to 15 nm thickness) and thin (15 nm - 150 nm thickness) layers. Nevertheless, analyses of KPFM surface potential measurements associated with results from Finite Element Modelling of the structures show that the dielectric layer thickness has weak influence on the amount of injected charges and on the decay dynamics, meaning that pretty homogeneous layers can be processed. The charge penetration depth in such dielectric layers is evaluated to 10 nm regardless the dielectric thickness.

中文翻译：

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介电层厚度对薄氧氮化硅层中电荷注入、积累和传输现象的影响：纳米级研究

薄介电层中的电荷注入和保留仍然是关键问题，因为它们造成了大量的故障机制。更好地理解和控制薄介电薄膜中的电荷注入、俘获和传输现象是提高电子和电气设备中介电部件的寿命和可靠性的重中之重。导热二氧化硅是一种极好的电介质，但对于当前的许多技术发展来说，需要更灵活的工艺来合成高质量的电介质材料，例如使用等离子体方法合成无定形氮氧化硅层。在本文中，研究的介电层是等离子体沉积的 SiOxNy。独立于层厚度，它们在结构上是相同的：光学透明，具有相同的折射率，等于导热硅胶之一。使用开尔文探针力显微镜 (KPFM) 和导电原子力显微镜 (C-AFM) 在纳米尺度研究介电膜厚度对此类层中充电现象的影响。介电膜厚度变化的主要影响涉及电荷注入步骤期间层中的电荷流动。根据 SiOxNy 层厚度，发现了测量的表面电位和电流的两个不同趋势，从而定义了超薄（最高 15 nm 厚度）和薄（15 nm - 150 nm 厚度）层。然而，与结构的有限元建模结果相关的 KPFM 表面电位测量分析表明，介电层厚度对注入电荷量和衰减动力学的影响较弱，这意味着可以处理非常均匀的层。无论电介质厚度如何，这种电介质层中的电荷穿透深度都被评估为 10 nm。