8-1 A TCAD Study on Mechanism and Countermeasure for Program Characteristics Degradation of 3D Semicircular Charge Trap Flash Memory

A TCAD model to simulate program/erase characteristics of 3D charge trap flash memory cells is constructed and calibrated with the experiment. The mechanism of the program characteristics degradation of the semicircular cells are studied using the TCAD model and it is clarified that the current leakage path due to the fringe parasitic transistor causes the degradation. An initial charge injection technique is proposed to suppress the parasitic leakage current to improve the program characteristics of the semicircular cells.