Sensitivity of Low-Frequency Noise to Thermal Stress in a Graphene-on-SiC Hall Effect Sensor Dedicated to Elevated Temperatures

We studied the effect of abnormal thermal stress on a graphene-on-SiC Hall effect sensor dedicated to elevated temperatures. After subsequent thermal stresses at 823, 873, and 923 K provided by rapid thermal processing (RTP), we monitored the transport parameters of a sensor (sheet resistance, mobility, and carrier concentration) and its low-frequency noise (LFN). We showed that RTP increases the average carrier concentration and widens its distribution across the device, as confirmed by Raman spectroscopy. We observed that the LFN magnitude significantly increases after subsequent stresses, much more than the average resistance, which decreases. The evaluation of thermal stress in electronic devices should include the noise-based method because it seems to be a much more sensitive indicator of thermal degradation than typically monitored electronic transport parameters. We showed that the RTP promotes nonhomogeneity within the sensor, the presence of which is directly exposed by the LFN measurements. Moderate thermal degradation (noise and resistances) up to 873 K suggests that the graphene-on-SiC Hall platform is promising for magnetic field detection at elevated temperatures. Furthermore, the methodology of 1/f noise analysis is universally applicable whenever the noise model of the active layer can be represented by a resistance network.