Surface treatment process using photoemission-assisted plasma for achievement of atomic scale flattened surface

光导等离子体离子源是一种用于将金属衬底表面平整至原子尺度粗糙度的离子源。在本研究中，通过Langmuir探针测量估算了离子撞击表面的动能（Ek），得到了0.1-30 eV的PAP的Ek。在低能（< 30 eV）和变化离子影响（< 1018 cm-2）下，用~13 nm的Ra(0)对cu - Si衬底进行PAP辐照。原子力显微镜对表面进行分析，表面粗糙度与Ra(0)相比降低了15~70%。然而，由于高离子辐照，在表面形成突起，导致表面粗糙度增加。从离子能量和离子影响的角度揭示了控制表面形貌变化的实验条件。根据观察结果，认为低Ek的PAP诱导表面原子的表面迁移增强对形貌变化起着至关重要的作用。

Photoemission-assisted plasma (PAP) ion source has been developed for flattening surface morphology of metal substrates down to an atomic-scale roughness. In this study, ion kinetic energy (Ek) of impinging on surface was estimated by Langmuir probe measurement, resulting in Ek of PAP with 0.1-30 eV. PAP irradiations to Cu-deposited Si substrates with Ra(0) of ~13 nm were conducted in low energy (< 30 eV) and changing ion fluence (< 1018 cm-2) regime. From the surface analysis by atomic force microscopy, surface roughness were reduced down to 15~70% compared of Ra(0). However, protrusions formed on the surfaces due to high ion fluence irradiation, which caused increase of surface roughness. The experiment conditions that control the surface morphology changes are revealed from the aspect from ion energy and ion fluence. Based on the observations, it is considered that surface migration enhancement of surface atoms induced by low Ek of PAP plays a vital role for the morphology changes.