Improved Variability of 2T0C DRAM via Specific Post-Treatment Suppressing Variable IGZO Capacitance

The voltage drops on the storage node (VSN) determined by the write transistor during data writing and keeping become the major challenge of stable operations in 2T0C DRAM even after optimizing the property uniformity in the read transistor. In this work, we unveil the key role of variable IGZO MOS capacitances on the memory stability based on a 2T0C DRAM scheme with 10-ks retention. By the specific oxygen compensated hydrogen self-adaptive-doping method, the total VSN drop and variation decreases by 22% and 75%, respectively. Benefitted by the uniform distribution of donor defect and interface state in the write transistor, we demonstrate a record-low VSN drop variation <20 mV and ultra-stable read characteristics of 2T0C DRAM. These results pave the way for the large-scale integration of stable multibit DRAM arrays in future.