Study of Thyristor-Mode Dual-Channel NAND Flash Devices

A novel dual-channel 3D NAND device was proposed previously [1]. In addition to the N- and P-channel read operations, such device can also perform a special "thyristor mode" which possesses super steep subthreshold slope (S.S. ~0). In this work, we studied 4 different types of read methods with the same device, which are normal N- and P-channel read, and thyristor-mode N- and P-channel read, respectively. These 4 different read methods can be carried out by just simply changing the bias arrangements of wordlines so that the IdVg curves can behave differently. An interesting finding is that the Vt window of P/E cycling and retention are quite different among these sensing methods. It may provide a new methodology to understand the charge storage mechanisms. This work provides a comprehensive study for understanding the operation physics of this novel device.