Ion assisted synthesis and modification of semiconductor structures
Ion technology offers great flexibility and compatibility with microelectronics CMOS technology. However, due to the unavoidable implantation damage, the quality of the resulting layers is inferior to epitaxial deposition (MBE or CVD) processes. The Institute of Ion Beam Physics and Materials Research (IIM) is leading the development of suitable short-time annealing methods (laser and flashlamp), which cause the implantation damage to heal and thus enable excellent material quality. A strategically important material system in this context is the Group IV alloy SiGeSn. The admixture of Sn to Ge causes a reduction of the energy gap, resulting in a direct semiconducting material. This enables the integration of more efficient optoelectronic devices on the chip. For many semiconductor devices, selective and high n- or p-doping is crucial, which often can only be achieved by ion implantation (hyperdoping). In the future, we will not limit ourselves to pure material development and characterization, but realize complete state of the art / high performance devices with special functionalities. In our clean room as well as nanofabrication facilities we prepare Si(GeSn) nanowires and on them nanowire field effect transistors (FETs). Neuromorphic circuits are realized in an ambipolar, reconfigurable design. Due to the large surface-to-volume ratio, nanowires also lend themselves to chemical or biosensors. A joint research group with the Institute of Radiopharmaceutical Cancer Research has recently been established to apply this technology in the biomedical field. The flash lamp technology is further developed in the Helmholtz Innovation Lab "Blitzlab" with regard to applications. The described technological processes also find applications in other material classes, e.g. magnetic materials or oxides.
Participating departments of the institute:
