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Investigation of gallium arsenide multilayer structures using a tunnelling microscope combined with a UHV‐SEM
Author(s) -
Albrektsen O.,
Salemink H.
Publication year - 1990
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/sia.740151104
Subject(s) - quantum tunnelling , epitaxy , heterojunction , auger electron spectroscopy , gallium arsenide , microscope , auger , materials science , optoelectronics , scanning tunneling microscope , semiconductor , perpendicular , optics , chemistry , nanotechnology , atomic physics , physics , geometry , mathematics , layer (electronics) , nuclear physics
Analysis of semiconductor multilayers in an ultrahigh vacuum (UHV) environment is performed using a tunnelling microscope built into a UHV‐SEM with an Auger facility. The GaAs (110) surface is investigated with tunnelling spectroscopy and topography. As this cleavage plane is perpendicular to the preferential 〈001〉 growth direction, several material properties along the growth direction can be monitored with atomic resolution. The system is equipped with an interlocked preparation chamber for UHV cleavage of samples and for preparation of tunnelling tips, which subsequently are transferred into the scanning tunnelling microscope (STM). The SEM is used to select the sample area for the STM, with a resolution of 25 nm. Examples of results are the tracing of p‐n junctions in (Al)GaAs heterostructures and the valence band alignment in GaAs/AlGaAs interfaces. Typically, these results are obtained with a spatial resolution of 1.0–1.5 nm and are compared with results from conventional experiments (luminescence or C – V measurements), which pertain to much larger sample areas. Finally, we discuss recent results on cross‐sections of MBE‐grown (Al)GaAs multilayers, with atomic resolution in the epitaxial layers and in their interfaces.