Set-up for post-irradiation determination of temperature during nuclear reactor exposure with 3C-SiC

Research reactors currently rely on thermocouples for accurate temperature measurements in instrumented rigs. However, a lot of irradiations are carried out in lower cost instrumented capsules without instrumentation where thermocouples are not an option. In the latter case calculations or melt wires are used to determine the irradiation temperature. These methods do not suffice for state-of-the-art irradiations where temperature needs to be accurately known. Cubic Silicon Carbide (3C-SiC) is a potential material to use as post-irradiation (PI) temperature monitor which theoretically allows the determination of the irradiation temperature. Recent developments at Idaho National Laboratory and Oak Ridge National Laboratory show the possibility to use 3C-SiC as a routine PI temperature monitor in un-instrumented capsules by observing changes in electrical resistivity after isochronal annealing. This is a challenging task as it requires accurate electrical measurements on a high-resistivity semiconductor, performed on activated samples and at high temperatures (up to 1000°C

Impact of firing on surface passivation of p-Si by SiO2/Al and SiO2/SiNx/Al stacks

Firing impacts on surface passivation provided by a SiO2 and SiO2/SiNx stack with evaporated Al films are studied by capacitance-based techniques on MIS capacitors. For devices with insulator layers consisting solely of as-deposited SiO2, the densities of either interface states (Dit) or fixed charges (Qfc) are hardly influenced by firing. Capping the SiO2 layer with a SiNx layer results in a shift of the peak activation energy of Dit toward the valence band (Ev) of Si. Firing this SiO2/SiNx stack leads to an increase of Qfc, a reduction of Dit, and a moderate shift of peak activation energy of Dit toward Ev. Co-firing with the Al film on top significantly reduces the Qfc, Dit, and Dit peak activation energy, which is resulting from the atomic hydrogen passivation. These results are of particular interest for the development of solar cells with rear surface passivation and local contacts