Atomic layer etching (ALE) of Ga-polar GaN (0001) using a standard inductively coupled plasma-reactive ion etching system is achieved in this work. The sequential process is using Cl₂ to modify the surface in the adsorption step. For the activation step, the authors compare two rare gas plasmas, namely, Ar and Kr, and show a much larger and well-defined ALE window for the latter. The ALE of GaN is demonstrated by etching mesa structures masked with a photoresist. A constant etching rate per cycle of two monolayers is obtained. The experimental conditions of this self-limited process are found by changing both the adsorption and activation times, together with the source power. This provides an atomic-scale process for nanofabrication, with significant improvements to the GaN surface.

中文翻译：

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GaN两种原子层刻蚀工艺的比较研究

在这项工作中，使用标准的电感耦合等离子体反应离子刻蚀系统实现了Ga极性GaN（0001）的原子层刻蚀（ALE）。顺序过程是在吸附步骤中使用Cl ₂修饰表面。对于活化步骤，作者比较了两种稀有气体等离子体，即Ar和Kr，并显示了后者更大，定义明确的ALE窗口。GaN的ALE通过蚀刻被光刻胶掩盖的台面结构来证明。获得两个单层的每周期恒定的蚀刻速率。通过改变吸附和活化时间以及源功率，可以找到这种自限过程的实验条件。这为纳米制造提供了原子尺度的工艺，并极大地改善了GaN表面。