Atomic scale interface structure of In{sub 0.2}Ga{sub 0.8}As/GaAs strained layers studied by cross-sectional scanning tunneling microscopy

Technical Report · Mon Nov 01 04:00:00 EST 1993

DOI:https://doi.org/10.2172/106626· OSTI ID:106626

Zheng, J F; Weber, E R ^[1]; Salmeron, M B ^[2]

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1. Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering
2. Lawrence Berkeley Lab., CA (United States). Materials Sciences Div.

A molecular beam epitaxy-grown In{sub 0.2}Ga{sub 0.8}As/GaAs strained layer structure has been studied by scanning tunneling microscopy in cross-section on the (110) cleavage plane perpendicular to [001] the growth direction. Individual indium atoms were differentially imaged in the group III sublattice, allowing, a direct observation of the interface roughness due to the indium compositional fluctuation. In the In{sub 0.2}Ga{sub 0.8}As layers, Indium atoms are found in clusters preferentially along the growth direction with each cluster containing 2--3 indium atoms. Indium segregation induced asymmetrical interface broadening is studied on an atomic scale. The interface of In{sub 0.2}Ga{sub 0.8}As grown on GaAs is sharp within 2--4 atomic layers. The interface of GaAs grown on In{sub 0.2}Ga{sub 0.8}As is found to be broadened to about 5--10 atomic layers. The atomic scale fluctuation due to indium distribution is about 20 {angstrom} alone the interface in this case. The authors conclude that clustering and segregation are the main reason for the In{sub 0.2}Ga{sub 0.8}As/GaAs interface roughness.

• Research Organization: Lawrence Berkeley Lab., CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 106626
• Report Number(s): LBL--35470; CONF-931108--115; ON: DE96000127
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
EXPERIMENTAL DATA
GALLIUM ARSENIDES
HETEROJUNCTIONS
INDIUM ARSENIDES
INTERFACES
MICROSTRUCTURE
ROUGHNESS