Fundamental Research of Molecular Beam Epitaxy for Device Applications.
Abstract
Characteristics of SnTe, Si, and Be were investigated as dopants in MBE of GaAs. SnTe exhibited substantially sharper doping profiles and lower surface segregations than elemental Sn. It appears that SnTe molecules incorporate mostly as Sn and Te pairs instead of independent Sn and Te atoms, and that this incorporation mechanism suppresses the surface segregation. It was also found that SnTe incorporation depends on the availability of Ga vacancies. The densities of Sn and Te and the SnTe-doped films were comparable, as expected from pair incorporation. The exact nature of the pair incorporation mechanism is not understood. It does not appear that SnTe incorporates as a molecule, since in that form it would give rise to a deep donor (25 meV-30 meV), which was not found in SnTe-doped films. DLTS measurements indicate that SnTe does not introduce detectable densities of deep traps in the film. Si was also studied in conjunction with accelerated growth rates. Si-doped films exhibited high mobilities and good photoluminescence (PL) characteristics. Lower energy peaks observed by others in liquid nitrogen temperature spectrum were not seen in our films, indicating these peaks are not inherently connected with Si doping. The accelerated growth rates did not affect the PL characteristics and only improved the liquid nitrogen mobilities. Be doping was studied in the range from 10 to the 16th power to 10 to the 19th power/cc. Satisfactory hole mobilities and p-n junctions were obtained, indicating adequate purity of the Be source. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1980
- Accession Number
- ADA096472
Entities
People
- Y. G. Chai