A multi-function memory array that includes a DRAM distributed in several DRAM sectors, a Flash EEPROM distributed in several Flash EEPROM sectors, a data bus interconnecting the DRAM sectors and the Flash EEPROM sectors, and a plurality of memory access control circuitries. Each DRAM sector and Flash EEPROM sector can be accessed independently and data can be transferred between a DRAM sector and a Flash EEPROM sector. External data can also be written into either DRAM or Flash EEPROM. Flash EEPROM in one sector is distributed in rows and columns, and cells in each column are separated from the cells in an adjacent column by deep trench isolation regions.