ONE-ELECTRON AND PHONON-ASSISTED TUNNELING IN N-Ge SCHOTTKY BARRIERS,
Abstract
The experimental tunneling conductance of metal-Ge contacts is compared to the predictions of the one-electron Schottky-barrier model in which all parameters are determined from experiments other than tunneling. Agreement is found in the magnitude and the shape of conductance vs bias curves for vacuum-cleaved, Sb-doped Ge units. The qualitative features of the As-doped units are also in agreement, but a discrepancy in magnitude exists. Substantially larger conductance is found in air-cleaved junctions than in vacuum- cleaved junctions. Capacitance measurements reveal that the barrier height for air-cleaved junctions is V sub b = 0.51V whereas V sub b = 0.63V for vacuum-cleaved junctions. Pronounced step increases in the conductance due to phonon-assisted tunneling occur at eV = plus or minus h omega where h omega is the energy of a Ge phonon at the Brillouin zone boundary along the <111> direction. Structure is clearly observed at all four phonon energies (TA, LA, LO, TO). The magnitude of the LA phonon-assisted tunneling is accounted for in a theoretical calculation bases upon a mechanism suggested by Kleinman to explain similar phenomena in Ge p-n junctions. The strength of the TA and LO phonon-assisted tunneling also appear to be in reasonable agreement with qualitative considerations, but the observed TO phonon-assisted tunneling is stronger than expected. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1969
- Accession Number
- AD0688837
Entities
People
- F. Steinrisser
- L. C. Davis