Surface structure and surface electronic states related to plasma cleaning of Si and Ge

Miscellaneous · Wed Jan 01 00:00:00 EST 1992

OSTI ID:5428427

Cho, J

This thesis discusses the surface structure and the surface electronic states of Si and Ge(100) surfaces as well as the effects of oxidation process on the silicon oxide/Si(100) interface structure. The H-plasma exposure was performed in situ at low temperatures. The active species not only remove microcontaminants such as oxygen and carbon from the surface, but also passivate the surface with atomic hydrogen by satisfying the dangling bonds of the surface atoms. The surfaces were characterized by Angle Resolved UV-Photoemission Spectroscopy (ARUPS) and Low Energy Electron Diffraction (LEED). In the case of Si(100), H-plasma exposure produced ordered H-terminated crystallographic structures with either a 2 x 1 or 1 x 1 LEED pattern. The hydride phases were shown to depend on the temperature of the surface during H-plasma cleaning. The electronic states for the monohydride and dihydride phases were identified by ARUPS. When the plasma cleaned surface was annealed, the phase transition from the dihydride to monohydride was observed. The H-terminated surface were characterized to have a flat band structure. For the Ge(100) surface, an ordered 2 x 1 monohydride phase was obtained from the surface cleaned at 180[degrees]C. After plasma exposure at [le]170[degrees]C a 1 x 1 surface was observed, but the ARUPS indicated that the surface was predominantly composed of disordered monohydride structures. After annealing above the H-dissociation temperatures, the shift in the spectrum was shown to occur with the dangling bond surface states. The H-terminated surfaces were identified to be unpinned. The interface structure of silicon oxide/Si(100) was studied using ARUPS. Spectral shifts were observed, which were dependent on the processes of surface preparation and oxidation. The shift was characterized in association with the band bending. The origins of the spectral shifts were discussed, including defects at interface and H-passivation in Si.

• Research Organization: North Carolina State Univ., Raleigh, NC (United States)
• OSTI ID: 5428427
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CRYSTALS
CLEANING
GERMANIUM
ELECTRONIC STRUCTURE
SURFACE PROPERTIES
SILICON
ELECTRON DIFFRACTION
OXIDATION
PLASMA
SPECTRAL SHIFT
TEMPERATURE RANGE 0400-1000 K
ULTRAVIOLET SPECTRA
CHEMICAL REACTIONS
COHERENT SCATTERING
DIFFRACTION
ELEMENTS
METALS
SCATTERING
SEMIMETALS
SPECTRA
TEMPERATURE RANGE
360602* - Other Materials- Structure & Phase Studies
360606 - Other Materials- Physical Properties- (1992-)