Sloped Sidewalls in 4H-SiC Mesa Structure Formed by a Cl2-O2 Thermal Etching

2007 ◽  
Vol 556-557 ◽  
pp. 733-736 ◽  
Author(s):  
S. Takenami ◽  
Tomoaki Hatayama ◽  
Hiroshi Yano ◽  
Yukiharu Uraoka ◽  
Takashi Fuyuki
Keyword(s):  
Electrical Properties ◽  
Etching Rate ◽  
Mesa Structure ◽  
Thermal Etching ◽  
Etching Method ◽  
Pn Junction ◽  
Etched Surface

Sloped sidewalls in 4H-SiC mesa structures on the (000-1) C face were formed by a Cl2-O2 thermal etching method. The etching rate of 4H-SiC (000-1) C face was 10 times faster than that of (0001) Si face, and the etching rate at 910oC was about 18μm/h. The etched surface was rather smooth, and the sidewall of the mesa was inclined to the off-axis substrate. Taking into account the off angle of about 8o toward [11-20] off direction, the angles of the sidewalls were 52-56o for the <1-100> and 55-57o for the <11-20> directions from the crystallographically accurate (000-1) C face. Epitaxial pn junction diodes with the sloped sidewalls structure were fabricated, which had good electrical properties.

Anisotropic Etching of SiC in the Mixed Gas of Chlorine and Oxygen

2008 ◽  
Vol 600-603 ◽  
pp. 659-662 ◽  
Author(s):  
Tomoaki Hatayama ◽  
T. Shimizu ◽  
Hiroshi Yano ◽  
Yukiharu Uraoka ◽  
Takashi Fuyuki
Keyword(s):  
Anisotropic Etching ◽  
Selective Etching ◽  
Mixed Gas ◽  
Etch Pits ◽  
Mesa Structure ◽  
Thermal Etching ◽  
Etching Method ◽  
Substrate Surfaces

Anisotropic thermal etching of 4H-SiC {0001} and {11-20} substrates was studied in the mixed gas of chlorine (Cl2) and oxygen (O2) over 900oC. Etch pits appeared only on the (0001) Si face. Etching rates depended on the temperature, O2/Cl2 ratio, and an etching direction on the substrate surfaces. When the mesa structure was formed by the selective etching method, sloped sidewalls were observed around the periphery of the mesa. The angle of sidewalls depended on the orientation of substrates.

scholarly journals Focused Ion Beam Etching of GaN

1999 ◽  
Vol 4 (S1) ◽  
pp. 769-774 ◽  
Author(s):  
C. Flierl ◽  
I.H. White ◽  
M. Kuball ◽  
P.J. Heard ◽  
G.C. Allen ◽  
...  
Keyword(s):  
Focused Ion Beam ◽  
Ion Beam ◽  
Etching Rate ◽  
Side Wall ◽  
Device Fabrication ◽  
Direct Write ◽  
Ion Beam Etching ◽  
Etched Surface ◽  
A Current ◽  
Established Technique

We have investigated the use of focused ion beam (FIB) etching for the fabrication of GaN-based devices. Although work has shown that conventional reactive ion etching (RIE) is in most cases appropriate for the GaN device fabrication, the direct write facility of FIB etching – a well-established technique for optical mask repair and for IC failure analysis and repair – without the requirement for depositing an etch mask is invaluable. A gallium ion beam of about 20nm diameter was used to sputter GaN material. The etching rate depends linearly on the ion dose per area with a slope of 3.5 × 10−4 μm3/pC. At a current of 3nA, for example, this corresponds to an each rate of 1.05 μm3/s. Good etching qualities have been achieved with a side wall roughness significantly below 0.1 μm. Change in the roughness of the etched surface plane stay below 8nm.

Sloped Sidewalls in 4H-SiC Mesa Structure Formed by a Cl2-O2 Thermal Etching

2007 ◽  
pp. 733-736
Author(s):  
S. Takenami ◽  
Tomoaki Hatayama ◽  
Hiroshi Yano ◽  
Yukiharu Uraoka ◽  
Takashi Fuyuki
Keyword(s):  
Mesa Structure ◽  
Thermal Etching

IN SITU ION BEAM ANALYSIS OF CHEMICAL AND PLASMA ETCHING OF Si

2001 ◽  
Vol 15 (28n29) ◽  
pp. 1419-1427
Author(s):  
KARUR R. PADMANABHAN
Keyword(s):  
Plasma Etching ◽  
Chemical Etching ◽  
Ion Beam ◽  
Etching Rate ◽  
Surface Damage ◽  
Moderate Increase ◽  
Ion Beam Analysis ◽  
Beam Analysis ◽  
Etched Surface

The possibility of carrying out in situ ion beam analysis of a gas-solid interface using RBS/Channeling techniques has been investigated using chemical and plasma etching of Si . A specially constructed thin Si window cell is used to initiate chemical etching of Si using Xe F 2. Analysis of etched Si surface using conventional, micro RBS/Channeling and computer simulated channeling spectra indicates a smooth damage free surface with fairly uniform etching. A moderate increase in etching rate and channeling χ min is observed in the presence of the analyzing beam. The results of chemical etching are compared with that due to Ar + and Xe + plasma induced etching of Si . In situ microbeam channeling analysis with CCM (Channeling Contrast Microscopy) of the plasma-etched surface indicates distinct differences in both etching rate and damage profile of Si (100) surface. The etching rate enhancement and damage profile have been explained using conventional TRIM analysis and ion beam surface damage.

Etching Method of the Fabrication Optical Tapered Fiber and its Formula

2011 ◽  
Vol 145 ◽  
pp. 520-524 ◽  
Author(s):  
Yan Tang Huang ◽  
Xiao Hua Wang ◽  
Ri Yan Bao
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Etching Rate ◽  
Fiber Surface ◽  
Optical Power ◽  
Etching Process ◽  
Etching Time ◽  
Mathematics Model ◽  
Tapered Fiber ◽  
Etching Method

Optical tapered fiber is one of the most high efficiency evanescent wave coupler for coupling light into and out the optical microcavity. We fabricated the tapered fiber with etching method in a designed groove with HF solution. This method was low cost, readily, and controllable. An etching groove had an oval in the middle and small V-shape towards both sides. HF solution was injected into the oval groove, while the deioned water was injected into the two V-grooves. Because of the solution diffusion, the etching rate was fast in the mid and decreased gradually towards both sides,the tapered fiber was fabricated. The optical power meter was monitoring the fiber transmission during the etching process. The transmission of the tapered fiber was 98%. We proposed a mathematics model to depict the etching process, containing the relationship between the diameter of tapered fiber and the concentration of the HF solution, the etching time, humidity, temperature. We supervised the optical intensity to deduce the tapered fiber diameter. Surface morphology with AFM was detected, the roughness of the tapered fiber surface is less than 1nm. As an evanescent coupler, we used the tapered fiber to transmit 980nm pump laser to couple to Er3+doped microsphere to stimulate 1557nm laser.

Properties of Thermally Etched 4H-SiC by Chlorine-Oxygen System

2007 ◽  
Vol 556-557 ◽  
pp. 283-286
Author(s):  
Tomoaki Hatayama ◽  
S. Takenami ◽  
Hiroshi Yano ◽  
Yukiharu Uraoka ◽  
Takashi Fuyuki
Keyword(s):  
Crystal Defects ◽  
Induced Current ◽  
Etch Pits ◽  
Thermal Etching ◽  
Oxygen System ◽  
Basal Plane Dislocation ◽  
Electron Beam Induced Current ◽  
Planar Mapping ◽  
Etched Surface ◽  
The Relationship

By the use of Cl2-O2 thermal etching method, the etching rates of 4H-SiC were reached to about 1μm/h for Si and 40μm/h for C face at 950oC. Etch pits only appeared over 0.25-μm-etched depth on the 4H-SiC (0001) Si face. The shapes and density of etch pits are similar tendencies in the case of molten KOH etched surface. To study the relationship between thermally etched surface features and crystal defects, the planar mapping electron-beam-induced current (EBIC) technique was carried out. Almost dark areas in the EBIC image correspond to the etch pits. From the EBIC image, a shell-like pit formed by the Cl2-O2 etching on the (0001) Si face is a basal plane dislocation.

Effect of Electrochemical Reaction Enviroment on the Surface Morphology and Photoluminescence of Porous Silicon

2013 ◽  
Vol 737 ◽  
pp. 60-66
Author(s):  
Ali Syari’ati ◽  
Veinardi Suendo
Keyword(s):  
Porous Silicon ◽  
Surface Morphology ◽  
Silicon Oxide ◽  
Quantum Confinement Effect ◽  
Etching Rate ◽  
Green Emission ◽  
Wet Etching ◽  
Electrochemical Anodization ◽  
Etching Method ◽  
Silicon Based

Porous silicon (p-Si) is a well-known silicon based material that can emit visible light at room temperature. The radiative recombination that originated from quantum confinement effect shows photoluminescence (PL) in red, while the defect on silicon oxide at the surface of p-Si shows in blue-green region. Porous silicon can be synthesized through two methods; wet-etching and electrochemical anodization using hydrofluoric acid as the main electrolyte. The electrochemical anodization is more favorable due to faster etching rate at the surface than the conventional wet-etching method. The objective of this research is to show that both of porous silicons can be synthesized using the same main electrolyte but by varying the reaction environment during anodization/etching process. Here, we shows the wet-etching method that enhanced by polarization concentration will produce porous silicon with silicon oxide defects by means blue-green emission, while direct electrochemical anodization will produce samples that emit red PL signal. The effect of introducing KOH into the electrolyte was also studied in the case of enhanced-wet-etching method. Surface morphology of porous silicon and their photoluminescence were observed by Scanning Electron Microscope and PL spectroscopy, respectively.

Morphological Instability of 4H-SiC (0001) Basal Plane Surface during Si-Vapor Thermal Etching

2012 ◽  
Vol 717-720 ◽  
pp. 577-580 ◽  
Author(s):  
Shoji Ushio ◽  
Kohei Nakanishi ◽  
Noboru Ohtani ◽  
Tadaaki Kaneko
Keyword(s):  
Basal Plane ◽  
Plane Surface ◽  
Etching Process ◽  
Morphological Instability ◽  
Free Surfaces ◽  
Mesa Structure ◽  
Thermal Etching

The morphological instability appeared at step-free 4H-SiC (0001) surfaces was investigated. The step-free surfaces were fabricated at the bottom of inverted-mesa structure by the method combining a laser digging and Si-vapor etching. By repeated Si-vapor etching treatments, randomly created crater and maze structures were cyclically appeared at the step-free surfaces. These structures were distinctly classifiable by their depths from the step-free surfaces. Crater structures have 0.2 - 0.3 nm depth and maze structures have 0.5 nm depth. The morphological evolutions indicate the process of destruction of the step-free (0001) basal plane and generation of steps from step-free surfaces in the Si-vapor etching process.

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