Melt pulled through shape-specific die - sheet (ribbon), tube or rod |
Top down, turn boule, fixed crucible, A axis |
Bottom up, fixed furnace and crucible, A axis |
GROWTH PROCESS |
Melt pulled through hot zones horizontally |
Sintering, pile of sapphire |
Pull crystal from melt and turn; diameter determined by pull rate |
Alumina oxide powder |
Alumina oxide powder, densified pellets |
Crackle |
FEED MATERIAL |
Multiple types |
Compacted feedstock |
Densified Charge |
Near net' shape - ribbon (sheet), tube, rod |
Boule (ingot) 'oversized paint can' |
Boule (ingot) |
OUTPUT SHAPE |
Slab |
Long narrow ingot (boule) |
Long narrow ingot (boule) |
Tubes / Rods up to 30" (750+mm) long; Sheets up to 18" dia x .400" thick |
13-15" dia A plane; 12" C plane; tubes 8" long |
13-15" dia A plane; 12" C plane; tubes 8" long |
DIMENSIONS |
350 x 500 x 40 mm, any orientation |
13 mm dia x 50 mm length max |
150 mm dia x 250 mm length |
Low optical grade , structural / mechanical |
Excellent, good clarity, consistent high optical quality |
Excellent, pink tint w/o annealing Grade 1-4 |
OVERALL MATERIAL QUALITY |
Excellent, good clarity, consistent high optical quality |
Excellent, good clarity, consistent high optical quality |
Excellent, good clarity, consistent high optical quality |
High |
Low |
Low |
DEFECT DENSITY |
Medium |
Low |
Low |
Low |
Med/High |
High |
TRANSMISSION |
Medium |
High |
High |
Average |
Excellent |
Excellent |
EASE OF FABRICATION |
Good |
Difficult |
Average |
Good for high volumes; ability to grow long tube, & rod; large sheet; low pricing |
Excellent for optical applications; adequate for substrate material |
Superior optical quality, transmission through entire spectrum; low cost |
ADVANTAGES |
Crystal dimensions not possible by any other growth methods; visual seed monitoring |
High optical transmission, material consistency |
Superior optical quality, transmission through entire spectrum; low cost |
Poor optical quality, high defect density |
Costly to abricate, cannot produce tubes |
Costly to abricate, cannot produce tubes |
DISADVANTAGES |
Some geometries costly to fabricate |
Small parts only |
Small parts only |
Low |
Medium |
High |
PRICE LEVEL |
Medium |
Medium / High |
High |