Fusion energy, when controlled, is extremely efficient and uses extremely abundant materials. The waste produced is far less in both quantity and risk compared with both fossil fuel and nuclear fission reactors. However, due to the specific conditions, extremely high temperatures and neutron irradiation from the plasma, required for fusion to occur the existing diagnostic and measurement systems simply will not perform as required. This extreme harsh environment such as related to ionizing radiation and high temperature conditions can seriously degrade electronic devices. For example, their levels in next-generation fusion reactors, such as ITER, can severely compromise or even cause permanent failure of many key diagnostics devices that are presently used in D-D magnetically-confined fusion plasma devices.
Semiconductor detectors play a very important role in plasma diagnostic. They can be used to detect neutron-induced charged particles and to monitor neutron beams in generators to count the number of charged particles emitted by deuterium–tritium (D–T) or deuterium–deuterium (D-D) fusion reactions. Unfortunately, neutron radiation introduces various defects into semiconductors, induces serious degradations in performance, and considerably shortens the lifetime of radiation detectors. Thus, it is important to develop robust detectors that survive the high radiation fluences and high temperature environment expected in plasma diagnostic.
Wide bandgap semiconductors, such as SiC, offer reduced leakage current when compared to silicon, which maintains low noise levels even at high temperatures and after irradiation at high fluences. Recent technology improvements, driven mainly by the power devices industry, in the production of the SiC material offer the possibility of using thick substrates and fabricating structures with small pitch electrodes on large active detection surfaces. This allows the fabrication of innovative radiation detectors in SiC that will be the only detectors capable of withstanding high radiation fluences and will be operated without cooling.
In this work we propose to the student to work on the simulation of SiC radiation detectors using Sentaurus TCAD simulation toolkit. The student will optimize the design of the detector to work at high temperature and will be modelling the bulk-damage effects in SiC radiation detectors.
The student will also have the chance to participate in the electrical characterization of the sensors in the radiation detector laboratory and will learn the main fabrication technology steps available in our clean room.