Electrical activation of arsenic implanted in silicon on insulator (SOI)

Abstract

Electrical activation of arsenic implanted in silicon on insulator (SOI) was studied. Two SOI structures with different Si overlayers and buried oxide thicknesses were used in this work. The As+ implantations were performed with a single energy of 20 keV to doses of 5 × 1014 cm−2 or 2 × 1015 cm−2 in both substrates. A plateau-like profile was achieved in an additional set of SOI samples by triple energy implantation. Rapid thermal and conventional furnace annealing were applied for dopant activation. Rutherford backscattering and Hall effect electrical measurements were done as well. The results are discussed, concerning electrical activation of As, considering the amorphization depth reached by dopant implantation and the crystal recovery process via thermal treatment. The completely amorphized samples presented higher values of sheet resistance and lower electrical activation percentage compared with the samples that did not have the complete top Si film amorphized. These results clearly show the need for avoiding total amorphization of the Si film during ion implantation in SOI, so that it is possible to achieve good crystal and electrical characteristics after thermal processing.

Hybrid magnetometers based on a doped silicon-on-insulator Hall device and a YBa2Cu3O7−δflux concentrator

“…In addition, incomplete recrystallization of the silicon layer prevents later epitaxial growth of YBCO. For thick Si top layers, implanting arsenic does not pose much of a problem because if proper implantation energies and doses are chosen, there will always be a crystalline layer of silicon leftover on top of an amorphous SiO 2 layer to act as a seed for the recrystallization [20]. Since in the current configuration the Si top layer is only 50 nm thick, special care has to be taken to prevent complete amorphization.…”

Process and Characterization of Hybrid-Oriented Complementary Single-Crystal Si Thin-Film Transistors on A Plastic Substrate

“…According to the previous doping study [9], the source/drain regions were ion implanted with phosphorus with a dosage of 1x10 16 /cm 2 at 12 KeV and boron with a dosage of 5x10 15 /cm 2 at 5 KeV for n-and p-TFTs respectively. Low-energy doping condition is chosen to suppress the ion damage, leaving more single-crystal material for a better recrystallization process, hence lower contact resistances and sheet resistances [10]. In order to form n-well for p-TFTs, the p-type template layers were further lightly doped with 3x10 11 /cm 2 phosphorus at 30KeV at designated regions to convert the channel into n-type.…”

Hybrid magnetometers for unshielded operation : combining hall sensors with superconducting flux concentrators

“…Numerous papers have been published where doping implantation in SOI wafers is investigated [118][119][120][121][122][123]. This includes analyses on the depth profile of the implanted doping and the activation of the doping by thermal annealing.…”

“…Doping of As on the other hand poses much more problems. There have been numerous reports that mention incomplete recrystallization which demonstrates itself by a decreased electrical activity with an increased doping density [118,121]. In [118] SOI is doped with As at implantation energies between 50 and 125 keV with a dose of 2 × 10 15 cm −2 .…”

“…That means that not all dopant atoms are active but a further increase of the temperature does not provide further electrical activation [121,123]. It is possible to perform the anneal procedure in-situ with the deposition of the superconducting YBCO flux concentrator and the maximum temperature this system can reach is about this temperature in vacuum.…”