Void formation and distribution in shaped sapphire crystals

Nicoarǎ, Irina; Nicoarǎ, Dumitru; Sofonea, Victor

doi:10.1016/0022-0248(90)90328-i

Cited by 17 publications

(20 citation statements)

References 11 publications

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“…Table 1 summarizes the important technical features of the growth processes. A detailed explanation about the growth conditions is given in the following reports [8,9,17,19]. A sketch of the two types of rod shapers is shown in Figure 2, one with central capillary channel (CCC) ( Figure 2a) and one with annular capillary channel (ACC) (Figure 2b).…”

Section: Methodsmentioning

confidence: 99%

“…The inductive heating in argon atmosphere is characteristic for two set-ups: the Sapphire 614 setup, in CEA-Grenoble [16] and the industrial pulling machine of Le Rubis SA, Jarrie, France. In the Safirom -set-up -Timisoara, Romania [8,9] the crystallization process takes place in vacuum using a graphite resistive heater. In all equipments, molybdenum has been used as crucible and shaper material.…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

On the void distribution and size in shaped sapphire crystals

Bunoiu¹,

Nicoarǎ²,

Santailler³

et al. 2005

Cryst. Res. Technol.

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Ribbon and rod sapphire pulling has been performed in three different crystal growth equipments in order to study the effect of the installation, of the atmosphere, of the die shape, of the feed material and of the pulling rate on the distribution, number and diameter of the characteristic voids (micro-bubbles) in the crystals. The location of the bubbles in the crystals depends on the die geometry; however, in most cases they are essentially located close to the crystal periphery and then can be efficiently removed by lapping. After statistical analysis of the results, it is demonstrated that the number of gas moles incorporated in the crystals, inside the voids, is totally independent of any growth parameter. It is also shown that the bubble diameter depends only on the pulling rate. Consequently, for a given pulling rate, the number of bubbles auto-adjusts in order to satisfy the constant molar gas incorporation.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

On the void distribution and size in shaped sapphire crystals

Bunoiu¹,

Nicoarǎ²,

Santailler³

et al. 2005

Cryst. Res. Technol.

View full text Add to dashboard Cite

show abstract

“…From many experiments [4][5][6][7][8][9][10]12] of shaped sapphire crystal growth it is evident that voids are trapped in the crystals. The available experimental data suggest that the void distribution depends on the fluid flow in the meniscus, and this is influenced by the die design [4,[6][7][8].…”

Section: Comparison With Experimental Data Related With Voids Distribmentioning

confidence: 99%

“…[1][2][3]. The characteristic defect in shaped sapphire crystals is the so-called voids or trapped gas bubbles [4][5][6][7][8][9][10], a defect that affects the optical and mechanical quality of the crystals, limiting their applications. In order to improve the crystal quality and process yield, it is important to know the causes of the voids formation and their distribution in the crystals.…”

Section: Introductionmentioning

confidence: 99%