Process for fabricating SOI compact contactless flash memory cell

摘要

A process for fabricating compact contactless flash memory array for semiconductor EEPROM devices having a number of memory cell units is disclosed. Field oxide layers for the flash memory array are first grown over the surface of an SOI wafer. Gate oxide layers are then grown. Floating gates are then formed by patterning the first polysilicon layer. Source/drain buried bitlines for the flash memory array are formed. A first BPSG (borophosphosilicate glass) layer is deposited and then reflown and etched back. An oxide-nitride-oxide layer is formed. A second polysilicon layer is deposited with in-situ dope. A WSix layer then forms. Stacked gates for the flash array are formed by patterning into the formed oxide-nitride-oxide, second polysilicon and WSix layers. The stacked gates are then covered with a second BPSG layer. Contact openings for the source/drain buried lines are formed. Metal lines leading into the contact openings are then formed for interconnecting the memory cells in the flash memory array with peripheral control circuits of the semiconductor EEPROM devices.