Lattice constant grading in the Al_yGa_1-yAs_1-xSb_x alloy system

Patent · Tue Jan 01 00:00:00 EST 1980

OSTI ID:863540

Moon, Ronald L ^[1]

---

1. Palo Alto, CA

Liquid phase epitaxy is employed to grow a lattice matched layer of GaAsSb on GaAs substrates through the compositional intermediary of the III-V alloy system AlGaAsSb which acts as a grading layer. The Al constituent reaches a peak atomic concentration of about 6% within the first 2.5 $$\mu$$m of the transition layer, then decreases smoothly to about 1% to obtain a lattice constant of 5.74 A. In the same interval the equilibrium concentration of Sb smoothly increases from 0 to about 9 atomic percent to form a surface on which a GaAsSb layer having the desired energy bandgap of 1.1 ev for one junction of an optimized dual junction photolvoltaic device. The liquid phase epitaxy is accomplished with a step cooling procedure whereby dislocation defects are more uniformly distributed over the surface of growing layer.

• Research Organization: Varian Associates, Inc., Palo Alto, CA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76ER01250
• Assignee: Varian Associates, Inc. (Palo Alto, CA)
• Patent Number(s): 4,195,305
• OSTI ID: 863540
• Resource Relation: Patent File Date: 1978 Sep 25
• Country of Publication: United States
• Language: English

Related Subjects

lattice
constant
grading
1-y
1-x
sb
alloy
liquid
phase
epitaxy
employed
grow
matched
layer
gaassb
gaas
substrates
compositional
intermediary
iii-v
algaassb
constituent
reaches
peak
atomic
concentration
transition
decreases
smoothly
obtain
74
interval
equilibrium
increases
percent
form
surface
desired
energy
bandgap
junction
optimized
dual
photolvoltaic
device
accomplished
step
cooling
procedure
whereby
dislocation
defects
uniformly
distributed
growing
uniformly distribute
transition layer
lattice constant
lattice matched
atomic percent
liquid phase
uniformly distributed
gaas substrate
phase epitaxy
energy band
energy bandgap
cooling procedure
compositional intermediary
dislocation defects
gaas substrates
gaassb layer
whereby dislocation
iii-v alloy
sb layer
matched layer
constant grading
/257/136/210/