Thermal stability of boron electrical activation in preamorphised ultra-shallow junctions

Deactivation of ultrashallow boron implants in preamorphized silicon after nonmelt laser annealing with multiple scans

“…This trend is consistent with deactivation resulting from the dissolution of EOR defects. 12,15,17 The lower amount of deactivation observed during the postannealing for the five-and ten-scan cases is similar to that observed by Lerch et al, 22 who found that flash-lamp annealing with a peak temperature of 1275-1325°C was sufficient to evolve the EOR defect band into dislocation loops. The supersaturation of interstitials at this stage of defect evolution is much lower than when ͕113͖ defects are present, and hence the amount of deactivation during postannealing, driven by this supersaturation, is also reduced.…”

“…13 The interstitials flow towards the surface and decorate the boron profile, producing boron interstitial clusters. [14][15][16][17] In this letter, multiple laser scan annealing at 1150°C followed by isochronal rapid thermal postannealing at lower temperatures is used to investigate the role of end-of-range defects in the redistribution and deactivation of ultrashallow B profiles in preamorphized and nonmelt laser-annealed silicon.N-type ͑100͒ Czochralski-silicon wafers were preamorphized with 5 keV Ge + to a dose of 1 ϫ 10 15 cm −2 producing a surface amorphous layer to a depth of ϳ15 nm. 500 eV B + was implanted into the amorphous layer to a dose of 1 ϫ 10 15 cm −2 .…”

Boron activation and redistribution during thermal treatments after solid phase epitaxial regrowth

“…Thus, low-temperature solid phase epitaxial regrowth (SPER) of preamorphized samples appears to be one of the most promising techniques for achieving acceptable sheet resistance and junction depth values to meet the performance specifications of the international technology roadmap of semiconductors (ITRS) [3]. Experiments show that preamorphizing implants (PAI) enhances dopant activation up to concentrations levels ∼10 20 cm −3 during low-temperature SPER of the amorphous layer, with a minimal amount of dopant diffusion [4][5][6][7][8][9][10]. Higher B concentrations are electrically inactive after the recrystallization process [5][6][7][8], which has been associated to the formation of immobile boron clusters [11,12].…”

“…Experiments show that preamorphizing implants (PAI) enhances dopant activation up to concentrations levels ∼10 20 cm −3 during low-temperature SPER of the amorphous layer, with a minimal amount of dopant diffusion [4][5][6][7][8][9][10]. Higher B concentrations are electrically inactive after the recrystallization process [5][6][7][8], which has been associated to the formation of immobile boron clusters [11,12]. The presence of residual defects at end of range (EOR) region, remaining after SPER beyond the amorphous/crystalline interface, leads to additional deactivation if annealing treatments are performed after the regrowth of the amorphous layer [5][6][7][8][9].…”

Strain-stabilized solid phase epitaxy of Si–Ge on Si

“…This process has also been used to improve structural quality 3 and enhance dopant activation. 4 With this method, the strain caused by the lattice mismatch places an upper limit of 3 -7 at. % on the amount of Ge that can be incorporated into the Si lattice before interfacial breakdown into a rough growth front occurs, causing the generation of defects, such as ͕111͖ facets and stacking faults, leading to severely degraded material not suitable for devices.…”