Abstract: The invention relates to a semiconductor device having a byte-erasable EEPROM memory comprising a matrix of rows and columns of memory cells. In order to provide a semiconductor device having a byte-erasable EEPROM which has a reduced chip size and increased density and which is suitable for low-power applications it is proposed according to the present invention that the memory cells each comprise a selection transistor having a selection gate and, arranged in series therewith, a memory transistor having a floating gate and a control gate, the selection transistor being further connected to a source line of the byte-erasable EEPROM memory, which source line is common for a plurality of memory cells, and the memory transistor being further connected to a bit line of the byte-erasable EEPROM memory, wherein the columns of memory cells are located in separate p-type wells separated by n-type wells.