Programmable semiconductor memory.

摘要

Memory cells (11) are divided into a plurality of series circuit units arranged in matrix fashion and comprising some memo @y cells connected in series. The memory cells each consist of non-volatile transistors provided with a control gate electrode, a floating gate electrode and an erase gate electrode. Bit lines (12) to which one end of each of the series circuit units of the plurality of series circuit units arranged in one row are connected in common. Column lines (14) are provided in common for the series circuit units that are arranged in one column and that are respectively connected to each control gate electrode of the memory cells constituting each of the series circuit unit. A voltage by which the selected non-volatile transistor works in a saturation state is applied to the control gate electrode of the selec @ed @ransistor of a series circuit unit by a column line, thereby injecting hot electrons from the semiconductor substrate into the floating gate electrodie. Another voltage by which the non-selected non-volatile transistor works in a non-saturation operation is applied to the gate electrodes of the remaining non-volatile transistors of the series circuit unit. By sequentially selecting memory cells in one series circuit unit, the sequential data writing operation is performed. The sequential data reading operation is performed in a similar manner.