ULTRA-SHALLOW RAISED P+-N JUNCTIONS FORMED BY DIFFUSION FROM SELECTIVELY DEPOSITED IN-SITU DOPED SI0.7GE0.3

In this paper, a novel raised p(+)-n junction formation technique is presented. The technique makes use of in-situ doped, selectively deposited Si0.7Ge0.3 as a solid diffusion source. In this study, the films were deposited in a tungsten halogen lamp heated cold-walled rapid thermal processor using SiCl2H2, GeH4, and B2H6. The microstructure of the Si0.7Ge0.3 layer resembles that of a heavily defected epitaxial layer with a high density of misfit dislocations, micro-twins, and stacking faults. Conventional furnace annealing or rapid thermal annealing were used to drive the boron from the in-situ doped Si0.7Ge0.3 source into silicon to form ultra-shallow p(+)n junctions. Segregation at the Si0.7Ge0.3/Si interface was observed resulting in an approximately 3:1 boron concentration discontinuity at the interface. Junction profiles as shallow as a few hundred angstroms were formed at a background concentration of 10(17) cm(3).