A non-volatile memory system that has junctionless transistors is provided that uses suppression of the formation of an inversion-layer source and drain in the junctionless transistors to cause a discontinuous channel in at least one string. The system may include NAND flash memory cells composed of junctionless transistors, and has a set of wordlines. During program operation, a selected wordline of the set of wordlines is biased at a program voltage, and wordline voltage low enough to suppress the formation of source/drains is applied on at least one word line on a source side of the selected wordline such that a channel isolation occurs thereby causing the discontinuous channel in the at least string.