Deep reactive ion etching of silicon carbide (original) (raw)
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A Review: Inductively Coupled Plasma Reactive Ion Etching of Silicon Carbide
Materials, 2022
The inductively coupled plasma reactive ion etching (ICP-RIE) is a selective dry etching method used in fabrication technology of various semiconductor devices. The etching is used to form non-planar microstructures—trenches or mesa structures, and tilted sidewalls with a controlled angle. The ICP-RIE method combining a high finishing accuracy and reproducibility is excellent for etching hard materials, such as SiC, GaN or diamond. The paper presents a review of silicon carbide etching — principles of the ICP-RIE method, the results of SiC etching and undesired phenomena of the ICP-RIE process are presented. The article includes SEM photos and experimental results obtained from different ICP-RIE processes. The influence of O2 addition to the SF6 plasma as well as the change of both RIE and ICP power on the etching rate of the Cr mask used in processes and on the selectivity of SiC/Cr etching are reported for the first time. SiC is an attractive semiconductor with many excellent properties, that can bring huge potential benefits thorough advances in submicron semiconductor processing technology. Recently, there has been an interest in SiC due to its potential wide application in power electronics, in particular in automotive, renewable energy and rail transport.
High-temperature etching of SiC in SF6/O2 inductively coupled plasma
Scientific Reports
In this work, we demonstrate an effective way of deep (30 µm depth), highly oriented (90° sidewall angle) structures formation with sub-nanometer surface roughness (Rms = 0.7 nm) in silicon carbide (SiC). These structures were obtained by dry etching in SF6/O2 inductively coupled plasma (ICP) at increased substrate holder temperatures. It was shown that change in the temperature of the substrate holder in the range from 100 to 300 °C leads to a sharp decrease in the root mean square roughness from 153 to 0.7 nm. Along with this, it has been established that the etching rate of SiC also depends on the temperature of the substrate holder and reaches its maximum (1.28 µm/min) at temperatures close to 150 °C. Further temperature increase to 300 °C does not lead to the etching rate rising. The comparison of the results of the thermally stimulated process and the etching with a water-cooled substrate holder (15 °C) is carried out. Plasma optical emission spectroscopy was carried out at di...
Reactive Ion Etching of 4H-SiC Using SF6/O2 for MEMS Application
2013
Deep Reactive Ion Etching (DRIE) of 4H-SiC performed using SF6/O2 plasma. The etching rates investigated as a function of the ratio of the O2 flow rate to total gas flow rate under different etching conditions such as the effect of power density, temperature, and the combination of chemistries on etching. The investigation was proven that the contribution and effect of the direct role of Oxygen to deep etching of SiC. An optimum value of O2 fraction of 60% to 40% Sulfur Hexafluoride (SF6) used to give high etching rate of 1.2μm/min. for maximum etching.
Reactive ion etching characterization of a-SiC: H in CF4/O2 plasma
Materials Science and Engineering: B, 1995
In this paper a reactive ion etching process on amorphous silicon carbide (a-SiC) films is characterized by varying the carbon content from 0.73 molar fraction of C (X,. = 0.73) to X~ = 0 (pure a-Si). The film composition was analyzed by electron microprobe analysis. The effect of hydrogen presence in the deposition chamber and of the material doping on the etch rate was considered. The etch rate in a CF4/O e plasma was investigated as a function of the r.f. power and gas pressure in the etching chamber, taking the loading effect also into account.
Scientific reports, 2017
This study presents a detailed fabrication method, together with validation, discussion, and analysis, for state-of-the-art silicon carbide (SiC) etching of vertical and bevelled structures by using inductively coupled plasma reactive ion etching (ICP-RIE) for microelectronic applications. Applying different gas mixtures, a maximum bevel angle of 87° (almost vertical), large-angle bevels ranging from 40° to 80°, and small-angel bevels ranging from 7° to 17° were achieved separately using distinct gas mixtures at different ratios. We found that SF6 with additive O2 was effective for vertical etching, with a best etching rate of 3050 Å/min. As for the large-angle bevel structures, BCl3 + N2 gas mixtures show better characteristics, exhibiting a controllable and large etching angle range from 40° to 80° through the adjustment of the mixture ratio. Additionally, a Cl2 + O2 mixture at different ratios is applied to achieve a small-angel bevels ranging from 7° to 17°. A minimum bevel ange...
Journal of Applied Physics, 2003
4H silicon carbide ͑SiC͒ substrates were dry etched in an inductively coupled plasma ͑ICP͒ system, using SF 6 /O 2 gas mixtures. Etch rate and etch mechanisms have been investigated as a function of oxygen concentration in the gas mixture, ICP chuck power, work pressure, and flow rate. Corresponding to these etch conditions, surface information of the etched SiC has been obtained by x-ray photoelectron spectroscopy measurements. The fact that no obvious Si-Si and Si-F bonds were detected on the etched surface of SiC in all our etch experiments suggests efficient removal of Si atoms as volatile products during the processes. However, various kinds of C-F bonds have been detected on the etched SiC surface and the relative intensities of these bonds vary with the etch conditions. In addition, the nature of the incorporated F atoms on the etched surface also depends strongly on etch conditions, which was identified by the change of the relative ratio between semi-ionic and covalent carbon fluorine bonds. The electrical behavior for different bond structures on the etched SiC surface can be one of the basic reasons affecting related devices.
Surface characterization of inductively coupled plasma etched SiC in SF6/O2
Microelectronic Engineering, 2003
An inductively coupled plasma (ICP) system has been used to dry etch 4H silicon carbide (SiC) substrate samples in SF / O gas mixture. Under different etching conditions, etch rates have been studied. Dry 6 2 etch-induced surface chemical bonding modifications have been systematically investigated using X-ray photoelectron spectroscopy (XPS). Various C-F bonds have been observed as etching products on the etched SiC surface. The increase of bias voltage and etch rate enhance not only the intensity of these C-F bonds but also the relative concentration of covalent C-F bonds on the etched SiC surfaces. Atomic force microscopy (AFM) results indicate that our etching process does not induce roughness on the etched surface even at higher bias voltages.
IOP Conference Series: Materials Science and Engineering, 2018
The features of the formation of non-vertical profiles on 4H-SiC by reactive-ion etching (RIE) using various masking coatings are studied. The formation of 4H-SiC mesa structures was carried out using automated airlock reactive-ion etching and plasma etching system "Caroline PE 15" with the ICP-source of plasma in a gas mixture of SF6, O 2 and Ar. Using photoresist AZ4533 as a mask, mesa structures with a wall inclination angle of more than 130° were obtained at the etching rate of 4H-SiC was ~0.5 μm/min. The developed technology of dry etching can be further used in the preparation of avalanche photodiodes or power electronics devices.