Aluminum Boron Nitride Ferroelectric Field-Effect Transistors With ZnO Semiconductor Channel

The discovery of ferroelectricity in hafnium zirconium oxide (Hf_xZr_1-xO₂) and related fluorite materials has spurred interest in ferroelectric devices suitable for integration with silicon integrated circuits (ICs), especially those that can be embedded in the back-end-of-line (BEOL) process. More recently, ferroelectricity has been found in wurtzite aluminum nitride-based materials, such as scandium and boron-doped aluminum nitride (Al_1-xSc_xN and Al_1-xB_xN). Although these materials currently have undesirably large coercive electric fields, and small breakdown electric field-to-coercive electric field ratio, their low processing temperatures and large remanent polarization offer intriguing possibilities for device applications. Here, we report ferroelectric field-effect transistors (FeFETs) with a 15 nm thick Al_0.88B_0.12N layer and an 11 nm ZnO semiconductor channel, achieving a memory window >1 V and switching voltages (V_switch) <±10 V.