High temperature diode sensors based on InGaN/AlGaN structures

Abstract

The authors have established the factors defining the maximum temperature limit of operating as well as the thermal sensitivity of the diode temperature sensors based on double heterostructures InGaN/AlGaN in a condition when tunnel current flow prevails. The authors have obtained analytic dependencies for the maximum temperature and sensitivity and have analyzed a connection of these characteristics with the parameters of the semiconductor material and the diode structure. In particular, it was shown that the sensitivity did not depend on the diode sensor operation current and, in the case of double heterostructure, its value was proportional to the energy gap difference of the heterojunction. Relying on the experimental data, the authors state that to design a diode temperature sensor possessing maximum values of operation temperature and thermal sensitivity at minimal operation current, it is necessary to utilize double heterostructures based on wide bandgap semiconductors. Base and emitter layers of the structure should be heavily doped. The optimal value of the energy gap difference between active and confining layers of about 0.2–0.3 eV should be provided. In addition, in the double heterostructure chosen, the tunnel transport of the charge carriers with smaller effective mass should dominate.