Increasing etching depth of sapphire nanostructures using multilayer etching mask

This paper presents a simple but reliable fabrication process for microfluidic devices on glass substrate using wet etching technology. Instead of using expensive Pyrex glasses as substrates and depositing expensive metal or polysilicon/amorphous silicon as etch masks in conventional method, glass slide is used as substrate and a single-layer negative photoresist RFJ-220 is used as the etching mask. The etch rates, generation of defects, undercut ratio and surface roughness are studied. In order to achieve high etching depth and smooth surface, buffered oxide etching with hydrochloric acid as additive is proposed. By proper cleaning and long-time hard baking, the undercut ratio can approach to 1. An 110μm depth microchannel with smooth surface is achieved. This fabrication process leads to a considerable reduction of process steps, fabrication time and material consumption. With this technique, we successfully fabricated a microfluidic device, which is used in the capture of hepatoma cells HepG2.

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Epitaxial regrowth of InP/InGaAs heterostructure on patterned, nonplanar substrates

Materials Science-Poland ◽

10.1515/msp-2016-0103 ◽

2016 ◽

Vol 34 (4) ◽

pp. 872-880 ◽

Cited By ~ 1

Author(s):

Łukasz Kosior ◽

Damian Radziewicz ◽

Iwona Zborowska-Lindert ◽

Andrzej Stafiniak ◽

Mikołaj Badura ◽

...

Keyword(s):

Epitaxial Growth ◽

Optical Microscope ◽

Dark Field ◽

Etching Depth ◽

Patterned Substrate ◽

Epitaxial Regrowth ◽

Mask Material ◽

Optical Profilometer ◽

Buried Heterostructure ◽

Etching Mask

AbstractThe main goal of the studies on epitaxial regrowth process of InP on patterned substrates is to gain knowledge about growth rates and interface quality on various areas to improve the fabrication technology for future applications. Prepared samples were measured at every step of the process by scanning electron microscope (SEM), optical microscope with dark field and phase contrast modes, atomic force microscope (AFM) and also using optical profilometer WLI (White Light Interferometer). Fabrication steps were divided into three main groups. First was the epitaxial growth of 5 µm thick InP layer. Next was patterning, which was made by applying a mask film on the epilayer. Shapes of the mesas after wet chemical etching with photoresist as a mask as well as the shapes of mesas slopes were irregular on the whole substrate area. These problems were solved by the use of silicon nitride mask. The mesas shapes and their slopes became then regular, independently of etching depth. Second fabrication step was etching of selected area. Couple of solutions were examined, but in details HCl:H3PO4 mixture in various proportions, which gave the best results in mesas shapes and orientations relative to the substrate. After that, the etching mask material was removed from the epilayer using a buffered hydrofluoric acid (BHF). The last step was epitaxial regrowth. To see how the epitaxial growth process was performed on different areas of patterned substrate it was suggested using a “sandwich”, which consisted of 50 layers of indium phosphide and indium gallium arsenide. This idea helped to understand the phenomena occurring during the epitaxial growth on that kind of substrate. The highest growth rate occurred on the top of the mesas and the lowest on their slopes. Described experiments are introduction to the studies on epitaxial growth of buried heterostructure (BH).

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Influence of Pixel Etching on Electrical and Electro-Optical Performances of a Ga-Free InAs/InAsSb T2SL Barrier Photodetector for Mid-Wave Infrared Imaging

Photonics ◽

10.3390/photonics8060194 ◽

2021 ◽

Vol 8 (6) ◽

pp. 194

Author(s):

Maxime Bouschet ◽

Ulises Zavala-Moran ◽

Vignesh Arounassalame ◽

Rodolphe Alchaar ◽

Clara Bataillon ◽

...

Keyword(s):

Dark Current ◽

Infrared Imaging ◽

Diffusion Length ◽

Lateral Diffusion ◽

Pixel Detector ◽

Dark Current Density ◽

Etching Depth ◽

Photo Response ◽

Wet Chemical ◽

Absorbing Layer

In this paper, the influence of etching depth on the dark current and photo-response of a mid-wave infrared Ga-free T2SL XBn pixel detector is investigated. Two wet chemical etching depths have been considered for the fabrication of a non-passivated individual pixel detector having a cut-off wavelength of 5 µm at 150 K. This study shows the strong influence of the lateral diffusion length of a shallow-etched pixel on the electro-optical properties of the device. The lowest dark current density was recorded for the deep-etched detector, on the order of 1 × 10−5 A/cm2 at 150 K and a bias operation equal to −400 mV. The corresponding quantum efficiency was measured at 60% (without anti-reflection coating) for a 3 µm thick absorbing layer. A comparison of experimental results obtained on the two kinds of etched pixels demonstrates the need for a deep-etching process combined with efficient passivation for FPA manufacturing.

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Research on Sapphire Deep Cavity Corrosion and Mask Selection Technology

Micromachines ◽

10.3390/mi12020136 ◽

2021 ◽

Vol 12 (2) ◽

pp. 136

Author(s):

Yiingqi Shang ◽

Hongquan Zhang ◽

Yan Zhang

Keyword(s):

Silicon Nitride ◽

Silicon Dioxide ◽

Chemical Vapor ◽

Nitride Layer ◽

Wet Etching ◽

Silicon Dioxide Layer ◽

Etching Depth ◽

Deep Cavity ◽

Mask Layer ◽

Layer Composite

Aimed at the problem of the small wet etching depth in sapphire microstructure processing technology, a multilayer composite mask layer is proposed. The thickness of the mask layer is studied, combined with the corrosion rate of different materials on sapphire in the sapphire etching solution, different mask layers are selected for the corrosion test on the sapphire sheet, and then the corrosion experiment is carried out. The results show that at 250 °C, the choice is relatively high when PECVD (Plasma Enhanced Chemical Vapor Deposition) is used to make a double-layer composite film of silicon dioxide and silicon nitride. When the temperature rises to 300 °C, the selection ratio of the silicon dioxide layer grown by PECVD is much greater than that of the silicon nitride layer. Therefore, under high temperature conditions, a certain thickness of silicon dioxide can be used as a mask layer for deep cavity corrosion.

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Manufacture of High Aspect Ratio Bulk Titanium Micro-Parts by Inductively Coupled Plasma Etching

2008 Second International Conference on Integration and Commercialization of Micro and Nanosystems ◽

10.1115/micronano2008-70125 ◽

2008 ◽

Cited By ~ 2

Author(s):

Gang Zhao ◽

Qiong Shu ◽

Yue Li ◽

Jing Chen

Keyword(s):

Aspect Ratio ◽

High Aspect Ratio ◽

Inductively Coupled Plasma ◽

Etching Rate ◽

Sidewall Roughness ◽

Inductively Coupled ◽

Icp Etching ◽

Novel Technology ◽

Micro Parts ◽

Etching Mask

A novel technology is developed to fabricate high aspect ratio bulk titanium micro-parts by inductively coupled plasma (ICP) etching. An optimized etching rate of 0.9 μm/min has been achieved with an aspect ratio higher than 10:1. For the first time, SU-8 is used as titanium etching mask instead of the traditional hard mask such as TiO2 or SiO2. With an effective selectivity of 3 and a spun-on thickness beyond 100 μm, vertical etching sidewall and low sidewall roughness are obtained. Ultra-deep titanium etching up to 200 μm has been realized, which is among the best of the present reports. Titanium micro-springs and planks are successfully fabricated with this approach.

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&[mu]-Watt Enhanced Electroluminescent Power of Silicon Nanocrystal Light-Emitting Diodes Made on Nano-Scale Silicon-Tip-Array Substrate

MRS Proceedings ◽

10.1557/proc-0989-a10-05 ◽

2007 ◽

Vol 989 ◽

Author(s):

Gong-Ru Lin ◽

Chun-Jung Lin

Keyword(s):

Light Emitting Diode ◽

Optical Power ◽

Oxide Semiconductor ◽

Si Substrate ◽

Light Emitting ◽

Pillar Array ◽

Turn On ◽

Air Interface ◽

Order Of Magnitude ◽

Etching Mask

AbstractA Si nanocrystal based metal-oxide-semiconductor light-emitting diode (MOSLED) on Si nano-pillar array is preliminarily demonstrated. Rapid self-aggregation of Ni nanodots on Si substrate covered with a thin SiO2 buffered layer is employed as the etching mask for obtaining Si nano-pillar array. Dense Ni nanodots with size and density of 30 nm and 2.8×10 cm-2, respectively, can be formatted after rapid thermal annealing at 850°C for 22 s. The nano-roughened Si surface contributes to both the relaxation of total-internal reflection at device-air interface and the Fowler-Nordheim tunneling enhanced turn-on characteristics, providing the MOSLED a maximum optical power of 0.7 uW obtained at biased current of 375 uA. The optical intensity, turn-on current, power slope and external quantum efficiency of the MOSLED are 140 μW/cm2, 5 uA, 2+-0.8 mW/A and 1×10-3, respectively, which is almost one order of magnitude larger than that of a same device made on smooth Si substrate.

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Platinum etching in Ar/O2 mixed gas plasma with a thin SiO2 etching mask

Journal of Vacuum Science & Technology A Vacuum Surfaces and Films ◽

10.1116/1.581050 ◽

1998 ◽

Vol 16 (2) ◽

pp. 502-508 ◽

Cited By ~ 23

Author(s):

Teruo Shibano ◽

Keisuke Nakamura ◽

Tatsuo Oomori

Keyword(s):

Mixed Gas ◽

Gas Plasma ◽

Etching Mask ◽

Sio2 Etching

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A Macroporous TiO2 Oxygen Sensor Fabricated Using Anodic Aluminium Oxide as an Etching Mask

Sensors ◽

10.3390/s100100670 ◽

2010 ◽

Vol 10 (1) ◽

pp. 670-683 ◽

Cited By ~ 34

Author(s):

Chih-Cheng Lu ◽

Yong-Sheng Huang ◽

Jun-Wei Huang ◽

Chien-Kuo Chang ◽

Sheng-Po Wu

Keyword(s):

Oxygen Sensor ◽

Aluminium Oxide ◽

Anodic Aluminium Oxide ◽

Etching Mask

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Holographic Pattern Etching of Silicon—Carbide by Excimer Laser

MRS Proceedings ◽

10.1557/proc-158-295 ◽

1989 ◽

Vol 158 ◽

Cited By ~ 5

Author(s):

M. Murahara ◽

M. Yonekawa ◽

K. Shirakawa

Keyword(s):

Laser Beam ◽

Present Method ◽

Etching Rate ◽

The Other ◽

Laser Beams ◽

Excimer Lasers ◽

Holographic Method ◽

Etching Depth ◽

Krf Laser ◽

193 Nm

ABSTRACTThe diffraction grating on SiC mirror was performed by a laser holographic method. In the present method, KrF laser and CIF3 was used for etchant gas. The ClF3 gas has an absorption band in the range between 200 and 400 nm. Therefore, CIF3 gas is effectively decomposed by the XeF, KrF and ArF excimer lasers' radiation. It is found that absorption of Si—C is about 50% in the range of between200 and 400 nm, and that the bonding energy of Si—C is lower than the photon energy of KrF laser beam. The above results indicate the direct decomposition of Si—Cbond. On the other hand, the threshold fluence energy for etching was 800 mJ/cm2 in 249 nm and in 193 nm as high as 7 J/cm2. In these results, the KrF laser is more effective than ArF laser. Then we applied KrF laser to crystalline SiC in an atmosphere of C1F3 gas. The divided two polarized KrF laser beams were interfered on the substrate. And the beams were used to photodissociated CIF3 gas in the proximity of substrate. Fluence of KrF laser beam was 1 J/cm2. The incidential angle of KrF laser beams was 20º and the grating gaps were 7170 Å, etching depth 1000 Å, and etching rate was 5 Å/pulse.

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Self-assembled quantum dots and nanoholes by molecular beam epitaxial growth and atomically precise in situ etching

MRS Proceedings ◽

10.1557/proc-722-k10.11 ◽

2002 ◽

Vol 722 ◽

Author(s):

S. Kiravittaya ◽

R. Songmuang ◽

O. G. Schmidt

Keyword(s):

Quantum Dots ◽

Molecular Beam ◽

Flat Surface ◽

Local Strain ◽

Growth Conditions ◽

Etching Depth ◽

Molecular Beam Epitaxial ◽

Self Assembled ◽

Molecular Beam Epitaxial Growth

AbstractEnsembles of homogeneous self-assembled quantum dots (QDs) and nanoholes are fabricated using molecular beam epitaxy in combination with atomically precise in situ etching. Self-assembled InAs QDs with height fluctuations of ±5% were grown using a very low indium growth rate on GaAs (001) substrate. If these dots are capped with GaAs at low temperature, strong room temperature emission at 1.3 νm with a linewidth of 21 meV from the islands is observed. Subsequently, we fabricate homogeneous arrays of nanoholes by in situ etching the GaAs surface of the capped InAs QDs with AsBr3. The depths of the nanoholes can be tuned over a range of 1-6 nm depending on the nominal etching depth and the initial capping layer thickness. We appoint the formation of nanoholes to a pronounced selectivity of the AsBr3 to local strain fields. The holes can be filled with InAs again such that an atomically flat surface is recovered. QDs in the second layer preferentially form at those sites, where the holes were initially created. Growth conditions for the second InAs layer can be chosen in such a way that lateral QD molecules form on a flat surface.

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