Amorphous silicon diodes as temperature sensors in microwave thermal ablation applications: an initial assessment

This article presents an initial evaluation of hydrogenated amorphous silicon (a-Si:H) p-i-n stacked structures to be used as temperature sensors in microwave thermal ablation (MTA). The diode behavior as a function of temperature has been characterized in air, in water, and in the presence of an electromagnetic (EM) field, irradiated by a commercial MTA antenna. The diodes proved to be able to measure temperatures up to the ones typical of the MTA technique, showing a stability better than 0.7 ° C/h in stressed working operation conditions (forward constant current equal to 500 nA at 125 ° C). Furthermore, in order to overcome the effect of the EM coupling with the diodes, a mathematical interpolation formula was developed allowing to rule out the EM coupling in real time during the MTA procedure. These preliminary results encourage the manufacturing of the diodes on flexible substrates in order to allow locating them directly on the MTA antenna shaft.