Vertical-channel Crystalline In2O3FET with a Pulled-up Gate, Monolithically Stacked on Si CMOS, Achieving 112.2 µA/µm On-state Current

We propose a 1T1C DRAM as a memory for artificial intelligence, formed with a vertical capacitor (VC) and a vertical-channel field effect transistor (VFET) that can be monolithically stacked on Si CMOS. The VFET improved its transient characteristics by adopting a gate with a pulled-up structure that reduces gate resistance and capacitance. Furthermore, VFET achieved high on-state current by using a crystalline indium oxide as a channel material. The VFET reduces its gate capacitance by 63.2% and a sheet resistance of a gate wiring by 95.1% as compared with a conventional structure, and improves its on-state current 8.3 times as that of the conventional structure. The 1T1C DRAM including VC and VFET monolithically stacked on Si CMOS takes 5 ns for reading and 5.5 ns for writing, and retains data for longer than 100 sec at 125°C, which achieves high-speed access and long-term retention.