The etching of InGaAs in acidic solutions of H2O2

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Nanoscale etching of III-V semiconductors in acidic hydrogen peroxide solution: GaAs and InP, a striking contrast in surface chemistry

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Nanoscale etching of III-V semiconductors in acidic hydrogen peroxide solution : GaAs and InP, a striking contrast in surface chemistry

In this study of nanoscale etching for state-of-the-art device technology, the importance of surface chemistry, in particular the nature of the surface oxide, is demonstrated for two III-V materials. Striking differences in etching kinetics were found for GaAs and InP in sulphuric and hydrochloric acidic solutions containing hydrogen peroxide. Under similar conditions, etching of GaAs was much faster, while the dependence of the etch rate on pH, and on H2O2 and acid concentrations also differed markedly for the two semiconductors. Surface analysis techniques provided information on the product layer present after etching: strongly non-stoichiometric porous (hydr)oxides on GaAs and a thin stoichiometric oxide that forms a blocking layer on InP. Reaction schemes are provided that allow one to understand the results, in particular the marked difference in etch rate and the contrasting role of chloride in the dissolution of the two semiconductors. A critical factor in determining the surface chemistry is considered to be the ease with which a proton can be removed from the group V hydroxide, which is formed in the initial etching step (the breaking of the III-V surface bond).peerReviewe

Photoanodic pyramid texturization of n-Ge(100) in HCl solution: unexpected anisotropy in the surface chemistry of etching

© 2019 The Royal Society of Chemistry. The process of electrochemical etching of n-Ge(100) surfaces was studied for aqueous HCl solutions by voltammetry, atomic force and scanning electron microscopy, reflectance measurements and X-ray photoelectron spectroscopy. Under applied potential conditions, unexpected random pyramid texturization was observed for the high HCl concentration range evidenced by the formation of characteristic (111) facets. The morphological changes were accompanied by a photocurrent enhancement and a decreased reflectance. By patterning the pyramids, a high structure density could be achieved. The resulting decrease of the reflectance indicates that the coupling of light into the semiconductor was improved. Integrated electrochemical X-ray photoelectron spectroscopy measurements allowed us to relate surface chlorination to the obtained morphological features. Photoanodic etching schemes are presented to provide insight into these striking results.status: publishe

Wet Chemical Processing of Ge in Acidic H(2)O(2)Solution: Nanoscale Etching and Surface Chemistry

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Amorphous Gadolinium Aluminate as a Dielectric and Sulfur for Indium Phosphide Passivation

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Atomic-scale investigations on the wet etching kinetics of GeversusSiGe in acidic H(2)O(2)solutions: a postoperandosynchrotron XPS analysis

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Photoanodic oxidation of InP in acid solution and its surface chemistry: On the interplay of photons, protons and hydrodynamics

Factors determining etching and passivation of n-type InP in H2SO4 and HCl solution and the corresponding surface chemistry are considered. Passivation is favoured by higher light intensity and lower proton and Cl− ion concentration. Ex-situ surface analysis shows the passive (bi)layer to consist mainly of oxide-based In3+ and P5+ components: InPO4 and In(PO3)3. Hydrodynamics is found to play a decisive and surprizing role in determining the kinetics of the surface reactions. Oxygen-bridge formation between surface In and P atoms, as a result of deprotonation of a P-OH reaction intermediate, is considered to be important in determining competition between the two reaction paths: etching and passivation. These results are compared with markedly contrasting results for n-type GaAs under similar experimental conditions