One approach to fabricate shallow junctions made of B-doped Si is to deposit B on Si, followed by knocking the B into the Si substrate with Si ions. Conventional belief is that the higher the implantation energy, the deeper the recoil profile. While this is true for low-energy incident ions, we show here that the situation is reversed for incident Si ions of higher energy due to the fact that recoil probability at a given angle is a strong function of the energy of the primary projectile. Our experiments show that 500 keV high-energy recoil implantation produces a shallower B profile than lower-energy implantation such as 10 and 50 keV. The secondary ion mass spectrometry analysis shows that the distribution of recoiled B atoms scattered by the energetic Si ions agrees with that calculated on the basis of interatomic potential suggested by W. D. Wilson, L. G. Haagmark, and J. P. Biersack [Phys. Rev. B 15, 2458 (1977)]. Sub-100 nm p+ /n junctions have been realized with a 500 keV Si ion beam.
ASJC Scopus subject areas
- Physics and Astronomy (miscellaneous)