An embodiment of a flash memory device with NAND architecture, including a matrix of data storage memory cells each one having a programmable threshold voltage, wherein the matrix is arranged in a plurality of rows and columns with the memory cells of each row being connected to a corresponding word line and the memory cells of each column being arranged in a plurality of strings of memory cells, the memory cells in each string being connected in series, the strings of each column being coupled to a reference voltage distribution line distributing a reference voltage by means of a first selector, wherein each string further includes at least one first shielding element interposed between the memory cells of the string and said first selector, the first shielding element being adapted to shield the memory cells from electric fields that, in operation, arise between the string of memory cells and the first selector.