Preliminary Study of the Chemical Polishing of a-Corundum Surfaces with Vanadium Pentoxide

Faktor, M. M.; Fiddyment, D. G.; Newns, G. R.

doi:10.1149/1.2426594

Cited by 7 publications

(5 citation statements)

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“…However, after treatment with one of the etchants (none of which dissolve sapphire at an appreciable rate at etching temperatures), the surface showed a highly scratched appearance. This effect has been noted by others (6). Hockey (10) has shown that after fine polishing, the surface is highly distorted and has a high dislocation density.…”

Section: Experimental Methodssupporting

confidence: 60%

“…The structure and the effect of electrolytic breakdown of anodic oxide films on silicon were considered by some authors (5,6). Schmidt and Owen (5) found that anodic films grown on silicon in phosphoric acid were of three types: completely structureless nonporous films, films with round spots of increased film thickness and films with round holes.…”

Section: Discussionmentioning

confidence: 99%

“…Schmidt and Owen (5) found that anodic films grown on silicon in phosphoric acid were of three types: completely structureless nonporous films, films with round spots of increased film thickness and films with round holes. Schmidt and Michel (6) found that electrolytic breakdown of anodic oxide films in p-type silicon was associated with severe damage to the oxides, when the voltage started to oscillate without rising any further. The present work is concerned with the morphology and structure of anodic films on silicon under electrolytic breakdown.…”

Section: Discussionmentioning

confidence: 99%

“…A number of chemical polishes have been reported. Besides the above mentioned phosphoric acid (2, 3), they include borax (4, 5) vanadium pentoxide (6), and potassium aluminum fluoride (3). Again, applicable orientation ranges are not well defined.…”

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confidence: 99%

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The Chemical Polishing and Etch Pitting of Sapphire

Vardiman

1971

J. Electrochem. Soc.

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Three dislocation etchants, H3PO4 , KOH , and KHSO4 , and two chemical polishes, H3PO4 and Na2B4O7 have been investigated as to their effective temperature and orientation ranges on sapphire. In addition the etchants are compared for effectiveness of dislocation pitting. It is found that the best pitting is obtained with KHSO4 on the false{2true1¯true1¯0false} plane, and KOH on the (0001) plane.

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Section: Experimental Methodssupporting

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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confidence: 99%

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The Chemical Polishing and Etch Pitting of Sapphire

Vardiman

1971

J. Electrochem. Soc.

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“…Depositions have also been performed on substrates cut from Czochralski boules, some of which have been mechanically polished only and other subsequently chemically polished in vanadium pentoxide, using the process developed by Faktor et al (1967). Silicon films have also been deposited on vapour grown (0001) plane platelets about 5 pm thick which were completely free from mechanical damage and were also virtually free from crystallographic imperfections except for a few growth steps.…”

Section: Substratesmentioning

confidence: 99%

The optimum conditions for the vacuum deposition of silicon on sapphire

Lawson¹,

Jefkins²

1970

J. Phys. D: Appl. Phys.

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The conditions under which good quality single-crystal silicon films can be vacuum deposited on to sapphire substrates have been established. The critical deposition parameters, which are shown to be interdependent, are the silicon impingement rate and the sapphire substrate temperature. For any given silicon impingement rate there exists an etching-deposition boundary temperature TE above which the silicon will etch away the sapphire and below which silicon is deposited. The etching-deposition boundary has been determined for the (011bar above 2) and (0001) sapphire orientations for silicon impingement rates in the range 0·1 to 1·5 μm min−1. The silicon film quality, in terms of its electrical mobility, is presented for the two orientations as a function of the parameter TD/TE, where TD is the substrate temperature and TE is the etching-deposition boundary temperature corresponding to the impingement rate used. There is an optimum value of TD/TE; under optimum conditions (111) silicon films deposited on (0001) sapphire have mobilities up to 75% of bulk values but are not very reproducible, while (001) silicon films deposited on (011bar above 2) sapphire have mobilities about 45% of bulk values and are reproducible. Whilst the macroscopic surface finish of the sapphire substrates is important, the crystalline perfection is not and the limited mobilities are ascribed to the high fault density of the films and the high compressive stress resulting from the thermal expansion mismatch.Although ultra-high vacuum techniques have been used throughout the work, evidence is presented which shows that the vacuum environment is not critical.

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Dislocation etch pits in anhydrous diglycine sulfate

Pandya

Vyas

1982

Cryst. Res. Technol.

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New dislocation etchants for anhydrous diglycine sulfate single crystals have been developed and the etching results are reported. Dichloroacetic acid, glacitel acetic acid and their mixtures work as dislocation etchants on the cleavage plane of the crystal. Morphology of the etch pits was found to vary with the etchant composition.Anhydrous diglycine sulfate single crystals (DGS) are grown from aqueous solution of glycine and sulfuric acid (WOOD, HOLDEN). The crystal structure is orthorohmbic and exhibit perfect cleavage parallel to (010) face. Most of the work reported in literature is related to the study of the growth of this crystal and the dielectric measurements along the crystallographic axes (WHIPPS et al.). The present authors have not come across any reference in the literature on dislocation studies in this crystal. New dislocation etchants developed by the present authors and variation in the morphology of etch pits with etchant composition are reported in this communication.Fairly large crystals of DGS were grown from aqueous solutions. Crystals were cleaved along (010) plane. Feshly cleaved surfaces were used in the present in estigation. The dislocation etchants developed are: 1) dichloro acetic acid (A. R. Quality), 2) glacial acetic acid (A. R. Quality), 3) mixture of dichloro acetic acid and glacial acetic acid in different proportions. Dichloro acetic acid reveals dislocations intersecting the cleavage plane producing elongated hexagonal pits (PANDYA, VYAS). Glacial acetic acid etches the crystal producing rectangular pits on the (010) plane. Figure l a shows the etch pattern produced on cleaved surface etched in glacial acetic acid. Figure l b shows elongated hexagonal pits produced on the opposite matched face etched in dichloro acetic acid.Fig. 1. a) Etch pattern on the cleavage plane etched in glacial acetic acid; b) Counter part of the crystal etched in dichlore acetic acidGeneral correspondence of the etch pits is observed in the photographs. Other experiments like sequential etching, etching of the indented surface etc., were also performed and it was confirmed that glacial acetic acid etches the cleaved surface producing rectangular pits a t the sites of emergence of dislocations.

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Preliminary Study of the Chemical Polishing of a-Corundum Surfaces with Vanadium Pentoxide

Abstract: not Available.

Cited by 7 publications

References 0 publications

The Chemical Polishing and Etch Pitting of Sapphire

The Chemical Polishing and Etch Pitting of Sapphire

The optimum conditions for the vacuum deposition of silicon on sapphire

Dislocation etch pits in anhydrous diglycine sulfate

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