Reactive Ion Etching of 4H-SiC Using SF6/O2 for MEMS Application (original) (raw)
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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.
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.
Deep reactive ion etching of silicon carbide
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2001
In this article, we describe more than 100-m-deep reactive ion etching ͑RIE͒ of silicon carbide ͑SiC͒ in oxygen-added sulfur hexafluoride ͑SF 6 ) plasma. We used a homemade magnetically enhanced, inductively coupled plasma reactive ion etcher ͑ME-ICP-RIE͒ and electroplated nickel masks. First, 5 h etching experiments using etching gases with 0%, 5%, 10% and 20% oxygen were performed by supplying rf power of 150 and 130 W to an ICP antenna and a sample stage, respectively. They demonstrated a maximum etch rate of 0.45 m/min and residue-free etching in the case of 5% oxygen addition. Observation of the cross sections of etched samples using a scanning electron microscope confirmed a microloading effect, which is reduction of the etched depth with a decrease in the mask opening width. Next, a 7 h etching experiment using an etching gas with 5% oxygen was performed by increasing the rf power to the sample stage to 150 W. This yielded an etched depth of 216 m.
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Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 1986
Reactive ion etching (RIE) using fluorinated gases, such as admixtures of CF 4 with 02 has been conducted on sputter deposited films of SiC. For comparison purposes, the same experiments with Si0 2 films and Si wafers have been conducted. The influence of RF power, pressure, and 02 concentration on etch rate in CF 4 + 02, SF 6 + He, and Ar gases has been investigated. RIE mechanisms were studied using in-situ monitoring of excited fluorine emission intensity and DC self bias at the lower electrode. Typical etch rates of Si, Si0 2 , and SiC are 1220 A/min., 600 A/min.,
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...
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.
ETCHING STUDIES OF POST-ANNEALED SiC FILMS DEPOSITED BY PECVD: INFLUENCE OF THE OXYGEN CONCENTRATION
Amorphous silicon carbide thin films (SiC) were produced by PECVD technique at room temperature. Post-annealing was used to crystallize the SiC films. These films were etched in reactive ion etching system using SF 6 + O 2 gas mixtures. The influence of O 2 concentration in process was investigated by mass spectrometry technique. Using this technique, it was possible to estimate the better conditions where the etching rates are optimal and also to verify the contributions of etchant species like F and O on the production of the main volatile products SiF 4 , CO and CO 2 .
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.
A Comprehensive Study of Hydrogen Etching on the Major SiC Polytypes and Crystal Orientations
Materials Science …, 2009
A comprehensive study on the hydrogen etching of numerous SiC polytype surfaces and orientations has been performed in a hot wall CVD reactor under both atmospheric and low pressure conditions. The polytypes studied were 4H and 6H-SiC as well as 3C-SiC grown on Si substrates. For the hexagonal polytypes the wafer surface orientation was both on-and off-axis, i.e. C and Si face. The investigation includes the influence of the prior surface polishing method on the required etching process parameters. 3C-SiC was also studied grown in both the and orientations. After etching, the samples were analyzed via atomic force microscopy (AFM) to determine the surface morphology and the height of the steps formed. For all cases the process conditions necessary to realize a well-ordered surface consisting of unit cell and sub-unit cell height steps were determined. The results of these experiments are summarized and samples of the corresponding AFM analysis presented. Z range 1.48 to -2.79 nm Z range 1.35 to -1.24 nm Z range 12.3 to -47.4 Z range 11.9 to -36.7 Z range 13.5 to -43.4 Z range 4.45 to -10.2 Z range 18.2 to -23.5 Z range 21.8 to -16.2 Z range 11.3 to -10.7 Z range 21.3 to -20.2