Doping for Germanium Technologies – DoGeTec

Context
The recent progress concerning the fabrication of large Ge mono- and poly-crystalline substrates, as well as Ge-On-Insulator (GOI) substrates, combined with the successful transfer of the high-k dielectric technology and of metallic contact fabrication from Si technology to Ge support the development of future high-performance Ge technology. This technology can be particularly useful for microelectronics and photovoltaic applications. However, in order to meet the restrictions for the fabrication of the next generation of miniaturized microelectronic devices, as well as to improve Ge-based solar cells, it is necessary to improve our knowledge concerning Ge doping. Presently, the possibility of creating highly-doped shallow p/n junctions in Ge is the main bottleneck preventing the development of an industrial Ge technology. Thus, it is necessary to study dopant implantation, implantation-mediated defects, dopant-defect interactions, dopant diffusion and dopant activation in Ge.
Project
The DoGeTec project aims to evaluate the potential of dopant elements (Al, Ga, Se and Te) for Ge doping, even if they are not currently used in Si technology. Furthermore, this project also aims to investigate the application for Ge doping of two doping techniques that already demonstrated their benefits in Si technology: namely the double same-type-dopant implantation (DI) and the solid phase epitaxy regrowth (SPER) techniques. The main goal of the project is to study defect (implantation-mediated defects…) interactions with dopants (segregation…) and dopant clustering in Ge, and to study their influence on dopant lattice diffusion during Ge post-implantation annealing. Performing fundamental investigations upon diffusion, cluster nucleation and growth, atom-defect interactions…, the DoGeTec project aims to propose solutions promoting reduced dopant diffusion (shallow junction), high incorporation and high dopant activation (high doping level), as well as reduced interactions between defects and dopants, which will allow the fabrication of efficient p+/n and n+/p junctions in mono-crystalline Ge.
Dopant diffusion, cluster formation and dopant-defect interactions will be studied using secondary ion mass spectrometry (SIMS), transmission electron microscopy (TEM) and laser-assisted atom probe tomography (APT). Dopant activation will be studied thanks to electrical measurements (resistivity, C-V and Hall Effect measurements).
Deliveries
The DoGeTec project aims to give access to fundamental experimental studies concerning atom diffusion in implanted Ge, considering atom clustering and atom-defect interactions. In addition, the project should be concluded by the fabrication of efficient p+/n and n+/p junctions in Ge using the best method determined by the study.
Environment
The researchers involved in the DoGeTec project are essentially young scientists that already worked on similar topics as those explored in DoGeTec but for Si technology. They are working in the Institute of Materials and Microelectronics and Nanoscience of Provence (IM2NP) that promotes the suitable environment for fundamental material science investigations related to microelectronics and photovoltaic applications.