High Temperature Hall Effect Sensor Based on Epitaxial Graphene on High Purity Semiinsulating 4H SiC
In this report, we demonstrate a novel high temperature Hall effect sensor that is based on quasi free standing monolayer graphene epitaxially grown on high purity semiinsulating (SI) on axis 4H SiC(0001) substrate in a chemical vapor deposition process. To ensure statistical perspective, characteristics of 23 elements are determined as a function of temperature ranging from 300 to 770 K. Passivated with a 100 nm thick atomic layer deposited aluminum oxide, the sensor offers current mode sensitivity of 80 V/AT with thermal stability of 0.02%/K within the range between 300 and 573 K, and 0.06%/K between 573 and 770 K. The sensor's room temperature output voltage is monitored in the magnetic field from 300 to +300 mT and its offset voltage at 0 T is assessed. Its high temperature electrical properties are explained through a double carrier transport involving spontaneous polarization induced holes in the graphene layer and thermally activated electrons emitted from a deep acceptor level related to silicon vacancy \text{V}_{\textsf {Si}\textsf {1 /2 occupying the {k} site of the 4H SiC lattice. The sensor is compared with a previously reported one on vanadium compensated SI on axis 6H SiC(0001) The new sensor's applicability to magnetic field detection at high temperatures is verified.
IEEE Transactions on Electron Devices