Fluorination of SiC with NF_3 by Plasma Assisted Reaction and Thermally Chemical Reaction

等离子体辅助反应和热化学反应用NF_3氟化SiC

• 批准号: 11650864
• 负责人: TASAKA Akimasa
• 金额: $ 1.47万
• 依托单位: Doshisha University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650864/
• 关键词: Nitrogen Trifluoride; Silicon Carbide; Plasma Etching; Anisotropic Etching; Smoothing; Spike; Optical Emission Spectroscopy; 反応性イオンエッチング

In the reactive ion etching (RIE) of SiC with NF_3, the etching rate was minimum at NF_3 pressure of 3 Pa. The surface of polished SiC specimen with treatment by RIE under conditions such as NF_3 pressure of 1 Pa and RF power of 100 W remained smooth in the scale of nm within 30 minutes, whereas it became rough in scale of 20 nm over 60 minutes. In contrast, the SiC surface became carbon-rich by RIE under NF_3 pressures higher than 3 Pa, because of the reaction of F radicals with Si on the SiC surface, and the carbon-rich part of SiC surface acted as a micromask to form spikes on it. The species such as N_2^+, N_2, and F radicals were observed in NF_3 plasma by optical emission spectroscopy. The physical etching by N_22^+ ion under lower NF_3 pressures and the chemical etching by F radicals under higher NF_3 pressures were preferentially occurred, respectively. Therefore, it is considered that the etching rate of 87 nm/min was obtained at NF_3 pressure of 0.5 Pa with RF power of 100 W, and that the depth of 2 μm was etched anisotropically with the smooth SiC surface in scale of nm. Analysis on the spike formation mechanism on the poly-SiC and SiC(111) specimens during RIE treatment revealed that the growth orientation of spike was independent of the critical face and the grain boundery on the SiC surface. The etching rates of the lattice planes such as (311) and (220) on the poly-SiC surface during Down Flow Etching (DFE) were small compared with those of (111), (200), and (222) lattice planes. On the other hand, the each etching rate for lattice planes mentioned above by sputtering with Ar^+ ion was almost equal to each other.

在NF_3的SIC的反应性离子蚀刻（RIE）中，在NF_3的压力为3 pa的情况下，蚀刻速率最低。在诸如NF_3压力为1 PA和RF的条件下，RIE处理的抛光SIC标本的表面在30分钟内保持在NM的尺度，并在30 nm的尺度上保持了60 nm的尺寸。相比之下，由于f自由基与SIC表面上的Si反应，SIC表面在NF_3下被RIE富含碳富含碳，并且SIC表面的碳富含碳的部分充当微型施加的微掩膜，以形成尖峰。通过光学发射光谱观察到NF_3等离子体中观察到N_2^+，N_2和F自由基等物种。在较低的NF_3压力下，N_22^+离子的物理蚀刻经常分别发生在较高的NF_3压力下的f自由基蚀刻。因此，认为以100 W的RF功率为0.5 pA的NF_3压力获得了87 nm/min的蚀刻速率，并且将2μM的深度蚀刻为各向异性，并以NM的平滑SIC表面为NM。在RIE处理过程中，对聚-SIC和SIC（111）标本的尖峰形成机理的分析表明，尖峰的生长取向与SIC表面上的临界面和晶界无关。与（111），（200）和（222）晶格平面相比，在下流蚀刻（DFE）期间，晶格平面（例如（311）和（220）的晶格平面（例如（311）和（220））很小。另一方面，上述晶格平面的每个蚀刻速率几乎彼此相等。