In the gate-recess formation process, normally-off operation is achieved by removing the barrier layer by dry etching to reduce the two-dimensional-electron-gas concentration under the gate electrode. An atomic-layer defect-free etching of GaN is thus indispensable to achieve high-frequency, high-power, and normally-off operation. More-precise atomic-layer defect-free GaN etching was investigated by using an HBr neutral beam. This investigation found that the HBr neutral beam could achieve more-precise atomic-layer etching than the Cl₂ neutral beam because the HBr chemistry can control the reactivity of atomic-layer etching by forming a thinner and less-volatile reaction layer.

中文翻译：

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使用HBr中性束对GaN进行原子层蚀刻

在栅凹槽形成工艺中，通过干法刻蚀去除势垒层以降低栅电极下方的二维电子气浓度来实现常关操作。因此，实现GaN的无原子层无缺陷蚀刻对于实现高频，高功率和常关操作是必不可少的。使用HBr中性束研究了更精确的原子层无缺陷GaN蚀刻。这项研究发现，HBr中性束可以比Cl ₂中性束实现更精确的原子层蚀刻，这是因为HBr化学物质可以通过形成更薄且挥发性较小的反应层来控制原子层蚀刻的反应性。