Influence of trench depth on the misfit dislocation density at strained epitaxial layer interfaces grown on patterned GaAs substrates

Journal Article · Mon Jun 03 04:00:00 EDT 1991 · Applied Physics Letters; (United States)

DOI:https://doi.org/10.1063/1.104862· OSTI ID:5686804

Watson, G P; Ast, D G ^[1]; Anderson, T J; Hayakawa, Y ^[2]

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1. Materials Science and Engineering Department, Cornell University, Ithaca, New York 14853 (USA)
2. Chemical Engineering Department, University of Florida, Gainesville, Florida 32611 (USA)

The number of misfit dislocations in strained, epitaxial InGaAs layers can be significantly reduced by growing on patterned substrates. Etched trenches on these substrates block misfit dislocation propagation from mesa to mesa. To determine the minimum trench depth needed to block misfit dislocations, 200 {mu}m{times}200 {mu}m mesas separated by 10-{mu}m-wide trenches of varying depths were etched into a GaAs substrate before organometallic chemical vapor deposition of 300 or 600 nm In{sub 0.04}Ga{sub 0.96}As strained layers (several times the critical thickness). Three isolation regimes are seen in the 300-nm-thick InGaAs samples. The shallowest trenches, regime I, below 300 nm, do not completely block all dislocations. Misfit dislocations are blocked by trenches 300--500 nm deep, regime II, after they glide down the mesa walls and stop at the far side of the trenches. Trenches greater than 500 nm, regime III, stop dislocations at the mesa edges. The 600-nm-thick InGaAs layers with trench depths greater than 450 nm completely stopped all misfit dislocations. The third regime did not occur for trenches as deep as 650 nm. These results show that the epitaxial layer does not have to be discontinuous to prevent misfit dislocations from gliding across patterned substrates.

• DOE Contract Number: FG02-86ER45278
• OSTI ID: 5686804
• Journal Information: Applied Physics Letters; (United States), Journal Name: Applied Physics Letters; (United States) Vol. 58:22; ISSN APPLA; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
ARSENIC COMPOUNDS
ARSENIDES
CHEMICAL COATING
CHEMICAL VAPOR DEPOSITION
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DEPOSITION
DISLOCATIONS
ETCHING
GALLIUM ARSENIDES
GALLIUM COMPOUNDS
INDIUM ARSENIDES
INDIUM COMPOUNDS
LINE DEFECTS
MICROSTRUCTURE
PNICTIDES
SURFACE COATING
SURFACE FINISHING