Small Al cluster ion implantation into Si and 4H-SiC

Xiaomei Zeng, Vasiliy Pelenovich, Alexei Ieshkin, Andrey Danilov, Alexander Tolstogouzov, Wenbin Zuo, Jha Ranjana, Donghong Hu, Neena Devi, Dejun Fu, Xiangheng Xiao

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

Rationale: Continuously downscaling integrated circuit devices requires fabrication of shallower p-n junctions. The ion implantation approach at low energy is subject to low beam current due to the Coulomb repulsion. To overcome this problem cluster ions can be used for implantation. In comparison with single ions, cluster ions possess lower energy per atom and reduced Coulomb repulsion resulting in high equivalent current. Methods: In this study to carry out low-energy implantation into single crystalline silicon and 4H-SiC samples we employ Aln (n = 1–5) clusters with energy in the range of 5–20 keV. The Al clusters are obtained by Cs sputtering of Al rod. Time-of-flight secondary ion mass spectrometry (TOF-SIMS; IONTOF TOF.SIMS-5) is used to study aluminum and oxygen sputter depth profiles for different cluster sizes and implantation energies before and after annealing treatment. Results: A distinguishable effect of the energy per atom in the cluster on reduction of the projected range Rp is revealed. The lowest Rp of 3 ± 1 nm has been achieved in SiC samples at the energy per atom of 1.66 keV. After annealing of Si samples, a considerable change in the Al profiles due to redistribution of Al atoms during motion of the front of recrystallization is observed. The influence of the number of atoms in the cluster at the same energy per atom within the experimental uncertainty is not observed. Conclusions: The transient effects of the sputtering by the primary ion beam distort the shape of the Al profiles in Si samples. In the case of SiC, due to its relatively lower surface chemical activity, more informative TOF-SIMS depth profiling of the shallow cluster implantation is feasible.

Original languageEnglish
Pages (from-to)1449-1454
Number of pages6
JournalRapid Communications in Mass Spectrometry
Volume33
Issue number18
DOIs
Publication statusPublished - 30 Sep 2019

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