Metal-ferroelectric AlScN-semiconductor memory devices on SiC wafers
Y. He, Shangyi Chen, Merrilyn Mercy Adzo Fiagbenu, Chloe Leblanc, Pariasadat Musavigharavi, Gwangwoo Kim, Xingyu Du, Jiazheng Chen, X.B. Liu, Eric A. Stach, Roy H. Olsson, Deep Jariwala
Abstract
This Letter presents oriented growth and switching of thin (∼30 nm) co-sputtered ferroelectric (FE) aluminum scandium nitride (AlScN) films directly on degenerately doped 4H silicon carbide (SiC) wafers. We fabricate and test metal ferroelectric semiconductor capacitors, comprising of Al/Al0.68Sc0.32N/4H-SiC. Our devices exhibit asymmetric coercive electric field values of −5.55/+12.05 MV cm−1 at 100 kHz for FE switching, accounting for the voltage divided by the depletion region of the semiconducting SiC substrate under positive voltages. Furthermore, the FE AlScN exhibits a remanent polarization of 110 ± 2.8 μC cm−2, measured via a voltage-pulsed positive-up negative-down measurement. We further investigate the reliability of the reported devices, revealing an endurance of ∼3700 cycles and a retention time of 9.5 × 105 s without any significant loss of polarization. Our findings demonstrate the bipolar switching of high-quality thin Al0.68Sc0.32N films on doped SiC substrates enabling monolithic integration of nonvolatile memory with SiC-based logic devices appropriate for high temperature operation as well as for high-power switching, memory, and sensing applications.