Controlled growth of semiconductor crystals

Patent · Wed Jan 01 00:00:00 EST 1992

OSTI ID:868396

Bourret-Courchesne, Edith D ^[1]

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1. Richmond, CA

A method 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.degree. 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.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• DOE Contract Number: AC03-76SF00098
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 5131975
• OSTI ID: 868396
• Country of Publication: United States
• Language: English

Related Subjects

controlled
growth
semiconductor
crystals
method
iii-v
ii-vi
related
single
suppresses
random
nucleation
sticking
melt
crucible
walls
pieces
oxide
boron
dispersed
throughout
comminuted
solid
charge
preferably
water
content
600
ppm
temperature
raised
m1
723
degree
allowed
form
reasonably
uniform
liquid
layer
bottom
surfaces
still-solid
approximately
m2
material
crystal
proceeds
encapsulated
vertical
gradient
freeze
process
half
grown
dislocation
density
1000
cm
nitride
inner
surface
oxidized
melted
thicknesses
50
semiconductor single
liquid layer
charge material
melt temperature
crystals grown
dispersed throughout
boron oxide
bottom surfaces
boron nitride
inner surface
single crystal
oxide layer
single crystals
crystal growth
bottom surface
water content
semiconductor charge
dislocation density
solid semiconductor
solid boron
semiconductor crystal
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