Surface photoabsorption study of the effects of growth temperature and V/III ratio on ordering in GaInP

Journal Article · Wed May 01 04:00:00 EDT 1996 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.361430· OSTI ID:283545

Murata, H; Ho, I H; Su, L C; Hosokawa, Y; Stringfellow, G B ^[1]

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1. Department of Materials Science and Engineering, University of Utah, Salt Lake City, Utah 84112 (United States)

Surface photoabsorption (SPA) measurements were used to clarify the Cu-Pt ordering mechanism in Ga{sub 0.5}In{sub 0.5}P layers grown by organometallic vapor phase epitaxy. The Cu-Pt ordering is strongly affected by the growth temperature and the input partial pressure of the phosphorus precursor, i.e., the V/III ratio. SPA was used to measure the concentration of [{bar 1}10]-oriented P dimers on the surface, which are characteristics of the (2{times}4) reconstruction, as a function of the growth temperature and V/III ratio. Degree of order decreases markedly with increasing growth temperature above 620 C at a constant V/III ratio of 40 [tertiarybutylphosphine (TBP) partial pressure of 50 Pa]. This corresponds directly to a decrease of the P-dimer concentration on the surface. Below 620 C, degree of order decreases as growth temperature decreases, even though concentration of P dimers increases. This is most likely due to slow migration of adatoms on the surface during growth. Degree of order is found to decrease monotonically with decreasing V/III ratio in the range from 160 to 8 at 670 C. This corresponds directly to decrease of P-dimer concentration on the surface. The direct correlation of the [{bar 1}10]-oriented P dimer concentration and degree of order with changes in both temperature ({ge}620 C) and V/III ratio suggests that the (2{times}4) surface reconstruction is necessary to form the Cu-Pt structure, in agreement with published theoretical studies. The physical structure of the surface of these Ga{sub 0.5}In{sub 0.5}P layers was also characterized, using atomic force microscopy. For growth at 670 C and a V/III ratio of 160, the structure of the layers growth on exactly (001) oriented GaAs substrates consists of islands surrounded mainly by bilayer (approximately 6 A) steps. As the V/III ratio is reduced, the step height transforms to one monolayer. Exclusively monolayer steps are formed at a V/III ratio of 8.

• OSTI ID: 283545
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 79; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ABSORPTION SPECTRA
FILM GROWTH
GALLIUM PHOSPHIDES
GROWTH
INDIUM PHOSPHIDES
STRUCTURAL CHEMICAL ANALYSIS
SURFACE PROPERTIES
SURFACE RECONSTRUCTION
TEMPERATURE DEPENDENCE
VAPOR PHASE EPITAXY
VPE