Photoluminescence from freestanding GaN with (1010) orientation

2003 ◽  
Vol 798 ◽  
Author(s):  
M. A. Reshchikov ◽  
A. Teke ◽  
H. P. Maruska ◽  
D. W. Hill ◽  
H. Morkoç
Keyword(s):  
Vapor Phase ◽  
Chemical Etching ◽  
Shallow Donor ◽  
Excitation Intensity ◽  
Structural Defects ◽  
Subsequent Removal ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Pl Spectrum ◽  
Lattice Matched

ABSTRACTFreestanding GaN templates with (1010) orientation (M-plane) were obtained by halide vapor phase epitaxy (HVPE) on nearly lattice-matched LiAlO2and subsequent removal of the substrate by wet chemical etching. Photoluminescence (PL) spectrum from both sides of the GaN template investigated is dominated by peaks at 3.47, 3.42 and 3.36 eV, tentatively attributed to an exciton bound to the neutral shallow donor and two unidentified structural defects, respectively. The quantum efficiency of the exciton-related emission exceeds 10%, whereas that of the combined emission from the defect-related bands (red, yellow and blue) is below 0.1%. The evolution of the PL spectrum with temperature and excitation intensity is analyzed in detail. Effects of polishing and etching on the PL properties are also discussed.

Defect Etching of Non-Polar and Semi-Polar Faces in SiC

2007 ◽  
Vol 556-557 ◽  
pp. 243-246
Author(s):  
Sakwe Aloysius Sakwe ◽  
Yeon Suk Jang ◽  
Peter J. Wellmann
Keyword(s):  
Chemical Etching ◽  
Structural Defects ◽  
Surface Polarity ◽  
Applied Method ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Etching Parameters ◽  
Kinetics Of

Wet chemical etching using molten KOH is the most frequently applied method to reveal structural defects in SiC. Until now etching kinetics of SiC in planes different from the polar cplane has not been reported. In this paper we report on defect etching of SiC in non-polar faces. Using a calibrated KOH defect-etching furnace with possibilities to set accurate etching temperatures we have etched SiC samples of various orientations to (i) study defect occurrence and their morphologies (ii) set KOH defect etching parameters for SiC for these orientations and (iii) investigate etching kinetics in relation to anisotropy/surface polarity. For non-polar planes of the same orientations a comparison in etching kinetics and defect morphologies in crystals grown in different directions is presented.

Effects of secondary pretreatments of substrate on the nucleation of diamond film

1996 ◽  
Vol 11 (7) ◽  
pp. 1787-1794 ◽  
Author(s):  
W. S. Yang ◽  
Jung Ho Je
Keyword(s):  
Plasma Etching ◽  
Chemical Etching ◽  
Diamond Powder ◽  
Structural Defects ◽  
Nucleation Density ◽  
Diamond Nucleation ◽  
Si Substrates ◽  
Nucleation Sites ◽  
Wet Chemical ◽  
Wet Chemical Etching

The effects of secondary pretreatments on diamond nucleation were investigated for the Si substrates pretreated by the diamond abrasion. When the substrate was just abraded with diamond powder, the nucleation density of diamond was 7 × 108/cm2. However, the nucleation density was found to be greatly decreased by various secondary pretreatments except by one wet chemical etching method. The nucleation density was reduced to 3 × 107/cm2 by the chemical etching (I), to 7 × 106/cm2 by the H2 plasma etching, and to ∼104/cm2 by the Ar sputtering, or O2 plasma etching. It was very slightly reduced to 3 × 108/cm2 by the chemical etching (II). The effects of secondary pretreatments in reducing the nucleation density were found to be very closely related to the removal of diamond seeds rather than topographic sites or structural defects. Therefore, diamond seeds generated by the diamond abrasion are considered as the main nucleation sites of diamond.

Decapsulation Techniques for Cu Wire Bonding Package

2009 ◽  
Author(s):  
Dongmei Meng ◽  
Joe Rupley ◽  
Chris McMahon
Keyword(s):  
Laser Ablation ◽  
Thin Layer ◽  
Chemical Etching ◽  
Wire Bonding ◽  
Methods And Techniques ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Reliability Issue ◽  
Etch Time ◽  
Device Technology

Abstract This paper presents decapsulation solutions for devices bonded with Cu wire. By removing mold compound to a thin layer using a laser ablation tool, Cu wire bonded packages are decapsulated using wet chemical etching by controlling the etch time and temperature. Further, the paper investigates the possibilities of decapsulating Cu wire bonded devices using full wet chemical etches without the facilitation of laser ablation removing much of mold compound. Additional discussion on reliability concerns when evaluating Cu wirebond devices is addressed here. The lack of understanding of the reliability of Cu wire bonded packages creates a challenge to the FA engineer as they must develop techniques to help understanding the reliability issue associated with Cu wire bonding devices. More research and analysis are ongoing to develop appropriate analysis methods and techniques to support the Cu wire bonding device technology in the lab.

scholarly journals Controlling the Facet of ZnO during Wet Chemical Etching Its (0001) O‐Terminated Surface

Small ◽  
2020 ◽  
Vol 16 (51) ◽  
pp. 2007045
Author(s):  
Mei Sun ◽  
Bocheng Yu ◽  
Mengyu Hong ◽  
Zhiwei Li ◽  
Fengjiao Lyu ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Wet Chemical ◽  
Wet Chemical Etching

scholarly journals In Situ Study of the Wet Chemical Etching of SiO2 and Nanoparticle@SiO2 Core–Shell Nanospheres

2021 ◽  
Author(s):  
Albert Grau-Carbonell ◽  
Sina Sadighikia ◽  
Tom A. J. Welling ◽  
Relinde J. A. van Dijk-Moes ◽  
Ramakrishna Kotni ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Core Shell ◽  
In Situ Study ◽  
Wet Chemical ◽  
Wet Chemical Etching

Controllable end shape modification of ZnO nano-arrays/rods by a simple wet chemical etching technique

2015 ◽  
Vol 48 (36) ◽  
pp. 365303 ◽  
Author(s):  
Jingchang Sun ◽  
Ting Zhao ◽  
Zhangwei Ma ◽  
Ming Li ◽  
Cheng Chang ◽  
...  
Keyword(s):  
Chemical Etching ◽  
Shape Modification ◽  
Etching Technique ◽  
Wet Chemical ◽  
Wet Chemical Etching

NOHSO4/HF – A Novel Etching System for Crystalline Silicon

2007 ◽  
Vol 62 (11) ◽  
pp. 1411-1421 ◽  
Author(s):  
Sebastian Patzig ◽  
Gerhard Roewer ◽  
Edwin Kroke ◽  
Ingo över
Keyword(s):  
Gas Phase ◽  
Chemical Etching ◽  
Silicon Surface ◽  
Crystalline Silicon ◽  
Etching Solution ◽  
Wide Range ◽  
Ft Ir ◽  
Wet Chemical ◽  
Wet Chemical Etching ◽  
Etching System

Solutions consisting of HF - NOHSO4 - H2SO4 exhibit a strong reactivity towards crystalline silicon which is controlled by the concentrations of the reactive species HF and NO+. Selective isotropic and anisotropic wet chemical etching with these solutions allows to generate a wide range of silicon surface morphology patterns. Traces of Ag+ ions stimulate the reactivity and lead to the formation of planarized (polished) silicon surfaces. Analyses of the silicon surface, the etching solution and the gas phase were performed with scanning electron microscopy (SEM), DR/FT-IR (diffusive reflection Fourier transform infra-red), FT-IR, Raman and NMR spectroscopy, respectively. It was found that the resulting silicon surface is hydrogen-terminated. The gas phase contains predominantly SiF4, NO and N2O. Furthermore, NH4+ is produced in solution. The study has confirmed the crucial role of nitrosyl ions for isotropic wet chemical etching processes. The novel etching system is proposed as an effective new way for selective surface texturing of multi- and monocrystalline silicon. A high etching bath service lifetime, besides a low contamination of the etching solution with reaction products, provides ecological and economical advantages for the semiconductor and solar industry.

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