Suppressed Electron-Phonon Scattering in Superlattices
CORNELL UNIV ITHACA NY SCHOOL OF ELECTRICAL ENGINEERING
Pagination or Media Count:
This report covers a three-year study of scattering of electrons by phonons in superlattices. The usual bulk polar optical phonons were confined to the quantum wells by the abrupt interfaces with the barriers. In short period superlattices this in turn would be expected to lower the rate of scattering of electrons by these phonons. This study showed that the room temperature mobility was reduced, rather than enhanced as expected from the phonon confinement. Interface phonon scattering was studied to show that it was the cause of the reduced mobility at room temperature. At lower temperatures, such as 77K and lower, the electron mobility measured was higher in the short period superlattice case when the barriers seen by the electrons were A1As. In order to avoid the interface phonon scattering, a graded composition quantum well was used. Devices made from such structures had improved electron mobility, breakdown voltage, and gate leakage.
- Electrical and Electronic Equipment
- Solid State Physics