Author(s)

Daniel Blaschke^1,2, Lars Rebohle², Ilona Skorupa², Heidemarie Schmidt^1,3

¹Leibniz Institute of Photonic Technology, Jena, Germany.
²Helmholtz-Zentrum Dresden-Rossendorf, Institute of Ion Beam Physics and Materials Research, Dresden, Germany.
³Friedrich Schiller University Jena, Institute for Solid State Physics, Jena, Germany.

The immobilization of biomaterials on a carrier is the first step for many different applications in life science and medicine. The usage of surface-near electrostatic forces is one possible approach to guide the charged biomaterials to a specific location on the carrier. In this study, we investigate the effect of intrinsic defects on the surface potential of silicon carriers in the dark and under illumination by means of Kelvin probe force microscopy. The intrinsic defects were introduced into the carrier by local, stripe-patterned ion implantation of silicon ions with a fluence of 3 × 10¹³ Si ions/cm² and 3 × 10¹⁵ Si ions/cm² into a p-type silicon wafer with a dopant concentration of 9 × 10¹⁵ B/cm³. The patterned implantation allows a direct comparison between the surface potential of the silicon host against the surface potential of implanted stripes. The depth of the implanted silicon ions in the target and the concentration of displaced silicon atoms was simulated using the Stopping and Range of Ions in Matter (SRIM) software. The low fluence implantation shows a negligible effect on the measured Kelvin bias in the dark, whereas the large fluence implantation leads to an increased Kelvin bias, i.e. to a smaller surface work function according to the contact potential difference model. Illumination causes a reduced surface band bending and surface potential in the non-implanted regions. The change of the Kelvin bias in the implanted regions under illumination provides insight into the mobility and lifetime of photo-generated electron-hole pairs. Finally, the effect of annealing on the intrinsic defect density is discussed and compared with atomic force microscopy measurements on the 2^nd harmonic. In addition, by using the Baumgart, Helm, Schmidt interpretation of the measured Kelvin bias, the dopant concentration after implantation is estimated.

Kelvin Probe Force Microscopy, Surface Potential, Intrinsic Defects, Silicon, Ion Implantation

Blaschke, D. , Rebohle, L. , Skorupa, I. and Schmidt, H. (2022) Local Tuning of the Surface Potential in Silicon Carriers by Ion Beam Induced Intrinsic Defects. Advances in Materials Physics and Chemistry, 12, 289-305. doi: 10.4236/ampc.2022.1211019.