Boron interaction with extended defects induced by He–H co-implantation in Si

Helium and hydrogen implantations lead to the formation of extended defects that strongly interact with impurities like metal and dopants, affecting significantly their final profiles. Even if the efficiency of this metal gettering technique is widely demonstrated in literature, the high dose requirement can be a drawback for industrial applications. Dose reduction becomes then crucial. In the smartcut® process, it has been shown that helium and hydrogen co-implantation leads to the expected dose decrease. The same idea was then applied for the gettering technique, keeping co-implantation doses below exfoliation threshold. evidencing the impact of the H addition on cavities, this paper will focus on boron interactions with He–H induced defects. For this purpose, uniformly high doped (1018 B cm−3) P-type <1 1 1> wafers were used. He implantation at 40 keV for a dose of 5 or 1 × 1016 He+ cm−2 followed or not by H implantation at 36 keV for different doses were carried out. Samples were subsequently furnace annealed for 1 h at temperatures ranging from 500 to 900 °C. Transmission electron microscopy (TEM) observations allow us to monitor the defect evolution. Secondary ion mass spectrometry (SIMS) was used to follow the boron and hydrogen profiles while the spreading resistance profiling (SRP) gives the activation dependence with the implantation and the annealing temperature. This work enlightens the large impact of H on cavity growth and clarifies the interaction of B with extended defects in presence or absence of hydrogen.