Ion irradiation of metal-semiconductor interfaces, and applications to electrical contacts

Miscellaneous · Sun Jan 01 00:00:00 EST 1989

OSTI ID:6280918

Hewett, Jr, C A

In the initial stages of this work the phase transformations in a number of ion implanted silicides were investigated. The results were interpreted as possible evidence for the existence of crystalline nuclei in the implanted silicide layer, even after high ion doses. In a study on the effect of ion mixing on multilayer samples with various layer thicknesses, it was found that for samples with an overall composition in a two phase region of the Ni-Si phase diagram equilibrium phases were always the first to form. At higher doses an amorphous phase was also present, but even at the very highest doses a crystalline equilibrium phase was observed, as expected from the initial study. Metal-silicon interactions in ion mixing may differ with those of the corresponding thermally annealed cases. Evidence is presented here that while the moving species under ion mixing appears to be strongly influenced by the implantation damage (defect) distribution in the sample, further experimentation indicated that the relative ranges of the secondary recoils may explain this observation. The final chapters of the dissertation consider the application of ion beam mixing to improving the electrical properties of devices. Ion mixing was found to decrease the interfacial roughness in PtSi/Si Schottky barrier diodes, while at the same time decreasing the reverse current and improving the uniformity in electrical characteristics from device to device. Irradiation was used to promote the formation of a SiC layer at a Si/diamond interface, leading to a Si/SiC/diamond graded bandgap structure. The contact resistance of such contacts was found to be comparable to the best ohmic contacts formed with Ta/Au, but with considerably less deviation.

• Research Organization: California Univ., San Diego, CA (USA)
• OSTI ID: 6280918
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
DIAMONDS
PHYSICAL RADIATION EFFECTS
NICKEL SILICIDES
PLATINUM SILICIDES
AMORPHOUS STATE
ANNEALING
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
ELECTRIC CONDUCTIVITY
ELECTRIC CONTACTS
ELECTRICAL PROPERTIES
GOLD
INTERFACES
ION BEAMS
ION IMPLANTATION
IRRADIATION
METALS
NICKEL
OPTIMIZATION
PHASE DIAGRAMS
PHASE TRANSFORMATIONS
PLATINUM
SCHOTTKY BARRIER DIODES
SEMICONDUCTOR DEVICES
SEMICONDUCTOR JUNCTIONS
SEMICONDUCTOR MATERIALS
SILICIDES
SILICON CARBIDES
TANTALUM
BEAMS
CARBIDES
CARBON
CARBON COMPOUNDS
DIAGRAMS
ELECTRICAL EQUIPMENT
ELEMENTAL MINERALS
ELEMENTS
EQUIPMENT
HEAT TREATMENTS
JUNCTIONS
MATERIALS
MINERALS
NICKEL COMPOUNDS
NONMETALS
PHYSICAL PROPERTIES
PLATINUM COMPOUNDS
PLATINUM METALS
RADIATION EFFECTS
SEMICONDUCTOR DIODES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
360206* - Ceramics
Cermets
& Refractories- Radiation Effects
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
360204 - Ceramics
Cermets
& Refractories- Physical Properties
360605 - Materials- Radiation Effects
360602 - Other Materials- Structure & Phase Studies
360603 - Materials- Properties