Performance of metal Hall sensors based on copper

We investigated potential of metal Hall sensors based on copper for steady state magnetic measurements on future fusion reactors. Prototype sensors were designed as thin copper active layer deposited on Al2O3 Direct Bond Copper (DBC) ceramic substrates with etched 0.127 mm thick copper contact areas and ceramic adhesive encapsulation. The active layers with thickness bellow 1 μm were fabricated by two alternative methods: vapour deposition and magnetron sputtering. The sensors reached the theoretically expected sensitivity values and showed repeatedly nearly no dependence of sensitivity on temperature up to 250 °C. We observed no effect of neutron irradiation on sensors properties up to the total neutron fluence of 1018 cm−2.