Etching of Si3N4 by SF6/H2 and SF6/D2 plasmas
Etching of Si3N4 by SF6/H2 and SF6/D2 plasmas
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SF6/H2 和 SF6/D2 等离子体蚀刻 Si3N4
DOI：
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
A. S. Smirnov
中科院分区：
文献类型：
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作者：
P. Pankratiev;Yuri Barsukov;A. Kobelev;A. Vinogradov;I. Miroshnikov;A. S. Smirnov
氮化硅（Si 3 N4）在氧化硅（SiO2）上的选择性等离子体蚀刻是纳米纤维工艺中的关键步骤之一，其中对于某些应用需要直接等离子体蚀刻Si 3 N4。最近有报道称，在低氟原子浓度下，HF（v）分子的振动激发可以引发远程等离子体源对Si_3N_4的刻蚀。通常，等离子体中HF（v）的主要来源是氟原子与H2分子的反应。因此，在Si_3 N_4刻蚀过程中，如果将H_2源气体替换为氘气（D_2），则应观察到动力学同位素效应。这里给出的数据是通过SF6/H2和SF6/D2等离子体的Si 3 N4和SiO2蚀刻。在Si 3 N4和SiO2蚀刻期间，将不同量的H2和D2添加到SF6放电中。结果表明，在低H2/D2流量下，SF6/D2放电中的Si 3 N4蚀刻速率较低。这一结果证实了关于HF（v）蚀刻Si 3 N4的假设，并表明HF（v）在相对高的原子氟浓度下对直接等离子体（而不仅仅是远程等离子体）蚀刻Si 3 N4有贡献。
Selective plasma etching of silicon nitride (Si3N4) over silicon oxide (SiO2) is one of critical steps in the nanofabrication processes, where a direct plasma etching of Si3N4 is required for some applications. It was reported recently that Si3N4 etching by remote plasma source can be initiated by the vibrationally excited HF(v) molecules at the low concentration of atomic fluorine. Generally, the main source of HF(v) in plasma is reaction of atomic fluorine with H2 molecule. Due to this fact, the kinetic isotope effect should be observed during Si3N4 etching if replace the H2 source gas on deuterium gas (D2). The data presented here are the Si3N4 and SiO2 etching by the SF6/H2 and SF6/D2 plasmas. A different amount of H2 and D2 have been added to the SF6 discharge during the Si3N4 and SiO2 etching. It was shown that at low H2/D2 flow rate the Si3N4 etch rate is lower in the SF6/D2 discharge. This one confirms the hypothesis about Si3N4 etching by HF(v) and indicates on the fact that HF(v) gives contribution to Si3N4 etching by the direct plasma (not only by the remote plasma) at relatively high concentration of atomic fluorine.