Controlled growth of semiconductor crystals

Patent · 21 July 1992

OSTI ID:7205481

Bourret-Courchesne, E D

A method is disclosed for growth of III-V, II-VI and related semiconductor single crystals that suppresses random nucleation and sticking of the semiconductor melt at the crucible walls. Small pieces of an oxide of boron B[sub x]O[sub y] are dispersed throughout the comminuted solid semiconductor charge in the crucible, with the oxide of boron preferably having water content of at least 600 ppm. The crucible temperature is first raised to a temperature greater than the melt temperature T[sub m1] of the oxide of boron (T[sub m1]=723 K for boron oxide B[sub 2]O[sub 3]), and the oxide of boron is allowed to melt and form a reasonably uniform liquid layer between the crucible walls and bottom surfaces and the still-solid semiconductor charge. The temperature is then raised to approximately the melt temperature T[sub m2] of the semiconductor charge material, and crystal growth proceeds by a liquid encapsulated, vertical gradient freeze process. About half of the crystals grown have a dislocation density of less than 1000/cm[sup 2]. If the oxide of boron has water content less than 600 ppm, the crucible material should include boron nitride, a layer of the inner surface of the crucible should be oxidized before the oxide of boron in the crucible charge is melted, and the sum of thicknesses of the solid boron oxide layer and liquid boron oxide layer should be at least 50 [mu]m. 7 figs.

• DOE Contract Number: AC03-76SF00098
• Assignee: Univ. of California, Oakland, CA (United States)
• Patent Number(s): US 5131975; A
• Application Number: PPN: US 7-551433
• OSTI ID: 7205481
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360601* -- Other Materials-- Preparation & Manufacture
BORON COMPOUNDS
BORON OXIDES
CHALCOGENIDES
CRYSTAL DEFECTS
CRYSTAL GROWTH
CRYSTAL STRUCTURE
CRYSTALS
DISLOCATIONS
LINE DEFECTS
MATERIALS
MELTING POINTS
MONOCRYSTALS
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SEMICONDUCTOR MATERIALS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE