Boron diffusion in silicon from metal boride sources
Thin films of titanium and lanthanum borides were investigated as potential boron diffusion sources. TiB{sub x} and LaB{sub 6} films exhibited room-temperature film stresses and resistivity values similar to refractory-metal silicides, and acted as boron diffusion sources, producing diffusions with high surface concentrations. The source of boron from TiB{sub x} films appears to be the excess boron present in the metal boride or at the metal boride-silicon substrate interface. Boron surface concentration increases with increasing mole fraction of boron in the metal boride source. Boron surface concentration peaks at 1000{degree}C for furnace-annealed TiB{sub 2.2}, but rises until a plateau is reached at 1050{degree}C for rapid-annealed samples of the same composition. The concentration of electrically active boron was consistently lower than the chemical concentration in these studies. The stability of the boride films on silicon substrates was found to be dependent on boride source composition. LaB{sub 6} and TiB films reacted with the silicon substrate. Although the TiB{sub 2.1}, TiB{sub 2.2}, and TiB{sub 2.9} films did not decompose or allow Si to diffuse into them, a silicon boride surface layer was formed in the silicon substrate caused by boron out-diffusing from these sources during furnace annealing.
- Research Organization:
- Rensselaer Polytechnic Inst., Troy, NY (USA)
- OSTI ID:
- 5178331
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360204* -- Ceramics
Cermets
& Refractories-- Physical Properties
BORIDES
BORON
BORON COMPOUNDS
DIFFUSION
ELEMENTS
FILMS
INTERFACES
LANTHANUM BORIDES
LANTHANUM COMPOUNDS
RARE EARTH COMPOUNDS
SEMIMETALS
SILICON
SUBSTRATES
THIN FILMS
TITANIUM BORIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS