Ultralow-Consumption Ferroelectric-Like Diamond Transistors for Advancing Logic Circuits

The relentless upscaling of chip integration density keeps urging microelectronic engineering to minimize the power consumption of individual field-effect transistors (FETs). However, due to the narrow bandgap and the relatively large dielectric constant of silicon, it has become nearly infeasible to further suppress the off-current in silicon-based FETs at advanced technology nodes. Moreover, the implementation of energy-efficient FETs is also precluded by the thermionic limit of subthreshold swing (SS) defined by Boltzmann's tyranny. Here, we report on the development of ferroelectric-like FETs through the integration of hydrogen-terminated diamond surface with a ZrO₂ capping layer, which exhibit an ultralow off-current (∼0.1 fA·µm⁻¹), a record-high on/off ratio (> 10¹¹), and a steep SS (6 mV·dec⁻¹) sustained well below the Boltzmann limit for over five decades of the drain current. The ZrO₂ capping layer shows a pronounced ferroelectric-like behavior with distinct polarization states. Based on structural analyses and positive-up negative-down (PUND) measurements, we speculate that the formation of dipolar polarization in the ZrO₂ layer is caused by the migration of oxygen vacancies, and the voltage-driven dipolar polarization switching can amplify the channel surface potential, which in turn leads to the outstanding off-state performance and the subthreshold current characteristics of the transistors. The FETs with great repeatability are employed to construct inverter circuits, which feature a high voltage gain exceeding 400 and significantly suppressed static power consumption. This study provides a promising pathway toward future low-power integrated circuits.