Improved Thermal Dissipation in a MoS2Field-Effect Transistor by Hybrid High-kDielectric Layers

Transition metal dichalcogenides like MoS2have been considered as crucial channel materials beyond silicon to continuously advance transistor scaling down owing to their two-dimensional structure and exceptional electrical properties. However, the undesirable interface morphology and vibrational phonon frequency mismatch between MoS2and the dielectric layer induce low thermal boundary conductance, resulting in overheating issues and impeding electrical performance improvement in the MoS2field-effect transistors. Here, we employed hybrid high-kdielectric layers of Al2O3/HfO2to simultaneously reduce the interfacial thermal resistance and improve device electrical performance. The enhanced contact, greater vibrational phonon overlapping region, and stronger interfacial bonding force between the top Al2O3layer and MoS2promote the heat removal efficiency across the interface to the substrate. Under the same input power density, the temperature profile of the MoS2transistor on the Al2O3/HfO2has been largely reduced compared to that of the device on HfO2, with a maximum reduction of 49.5 °C. In addition, the field-effect mobility and current of MoS2devices on the Al2O3/HfO2high-kdielectric layers have been significantly improved, attributed to the depressed electron scattering and trap states at the interface. The design of the hybrid high-kdielectric layers provides an efficient solution to simultaneously improve the thermal and electrical performance of the two-dimensional devices.