β-Ga₂O₃, known as a next-generation wide-bandgap transparent semiconducting oxide (TSO), has considerable application potential in ultra-high-power and high-temperature devices. However, fabricating a smooth β-Ga₂O₃ substrate is challenging owing to its strong mechanical strength and chemical stability. In this study, an atomic-scale smoothing method named plasma-enabled atomic-scale reconstruction (PEAR) is proposed. We find that three reconstruction modes, namely, 2D-island, step-flow, and step-bunching, can be identified with the increase in the input power; only the step-flow mode can result in the formation of an atomically smooth β-Ga₂O₃ surface (Sa = 0.098 nm). Various surface and subsurface characterizations indicate that the smooth β-Ga₂O₃ surface shows excellent surface integrity, high crystalline quality, and remarkable photoelectric properties. The atomic-scale density functional theory-based calculations show that the diffusion energy barrier of a Ga atom is only 0.46 eV, thereby supporting the atomic mass migration induced by high-energy plasma irradiation in the experiment. Nanoscale molecular dynamics simulations reveal that O atoms firstly migrate to crystallization sites, followed by Ga atoms with a lower migration rate; reconstruction mainly proceeds along the <010> direction and then expands along the <100> and <001> directions. The millimeter-scale numerical simulations based on the finite element method demonstrate that the coupling of the thermal and flow fields of plasma is the impetus for PEAR of β-Ga₂O₃. Furthermore, the smoothing generality of PEAR is demonstrated by extending it to other common TSOs (α-Al₂O₃, ZnO, and MgO). As a typical plasma-based atomic-scale smoothing method, PEAR is expected to enrich the theoretical and technological knowledge on atomic-scale manufacturing.

β -Ga ₂ O ₃被称为下一代宽带隙透明半导体氧化物（TSO），在超高功率和高温器件中具有巨大的应用潜力。然而，由于其强大的机械强度和化学稳定性，制造光滑的β -Ga ₂ O _{3衬底具有挑战性。}在这项研究中，提出了一种称为等离子体原子尺度重建（PEAR）的原子尺度平滑方法。我们发现随着输入功率的增加，可以识别出三种重建模式，即二维岛、阶梯流和阶梯聚束；只有阶梯流模式才能形成原子级光滑的β -Ga ₂ O ₃表面( Sa = 0.098 nm)。各种表面和亚表面表征表明，光滑的β -Ga ₂ O ₃表面表现出优异的表面完整性、高结晶质量和卓越的光电性能。基于原子尺度密度泛函理论的计算表明，Ga原子的扩散能垒仅为0.46 eV，从而支持了实验中高能等离子体辐照引起的原子质量迁移。纳米级分子动力学模拟表明，O原子首先迁移到结晶位点，其次是迁移速率较低的Ga原子；重建主要沿<010>方向进行，然后沿<100>和<001>方向扩展。基于有限元方法的毫米级数值模拟表明，等离子体热场与流场的耦合是β -Ga ₂ O ₃ PEAR的推动力。此外，通过将 PEAR 扩展到其他常见的 TSO（α -Al ₂ O ₃、ZnO 和 MgO），证明了 PEAR 的平滑通用性。作为一种典型的基于等离子体的原子级平滑方法，PEAR有望丰富原子级制造的理论和技术知识。