3D X-DRAM: A Novel 3D NAND-like DRAM Cell and TCAD Simulations

This paper presents a novel capacitorless 3D DRAM floating body cell using a 3D NAND-like cell structure known as 3D X-DRAM. This allows the cells to be manufactured using the mature 3D NAND process with minor changes to reduce the challenges in developing a new 3D DRAM process. This 3D X-DRAM cell uses a dual-gate, thin-body structure and a new operation mechanism that uses a back gate voltage to modulate the channel current. This cell can overcome all the problems in the traditional 2D floating body cells, including extremely small sensing windows, poor data retention time, and severe word line and bit line disturbances. This paper presents TCAD simulation results that show 3D X-DRAM cells can achieve higher than 20uA sensing window, longer than 200ms retention time at 85C, 1V operation voltage, and more than 10^16 endurance cycles. This makes 3D X-DRAM an excellent solution for future 3D DRAM and AI applications.