Diffusion-less ultra-shallow p+/n junction formation in Si using low-temperature solid phase epitaxy and non-melt laser annealing

Formation of ultra-shallow p⁺/n junction has been performed with the combination of low-temperature solid phase epitaxy and non-melt laser annealing. The former is aimed for improving crystallinity of junction region and the latter for activating implanted B ions. After pre-amorphization implantation of Ge, B ion implantation was performed at energy of 0.2 keV with a dose of 1.2 times 10¹⁵/cm². With adequate conditions, the junction depth around 8 nm with sheet resistance of 920 Omega/square is successfully formed in non-melting state. B dopant profile is kept almost with the as-implanted profile. In addition, the junction leakage current at reverse bias decreases dramatically with low-temperature solid phase epitaxy due to the reduction of residual defects.