Design of Ga2O3 modulation doped field effect transistors

The design of β-Ga2O3-based modulation-doped field effect transistors is discussed with a focus on the role of self-heating and resultant modification of the electron mobility profile. Temperature- and doping-dependent model of the electron mobility as well as temperature- and orientation-dependent approximations of the thermal conductivity of β-Ga2O3 are presented. A decrease in drain current was attributed to a position-dependent mobility reduction caused by a coupled self-heating mechanism and a high electric-field mobility reduction mechanism. A simple thermal management solution is presented where heat is extracted through the source contact metal. Additionally, it is shown that an undesired secondary channel can form at the modulation-doped layer that is distinguished by an inflection in the transconductance curve.