EEPROM device having improved data retention and process for fabricating the device

Abstract

An EEPROM device having improved data retention and process for fabricating the device includes a two-step deposition process for the fabrication of an ILD layer overlying the high voltage elements of an EEPROM memory cell. The ILD layer is fabricated by first depositing an insulating layer on a high voltage device layer and thermally treating insulating layer. A second insulating layer is then deposited to overlie the first insulating layer. An EEPROM device in accordance with the invention includes a floating-gate transistor having a specified threshold voltage. A thermally-treated, boron-doped oxide layer overlies the floating-gate transistor and a second oxide layer overlies the thermally-treated, boron-doped oxide layer. The memory device exhibits data retention characteristics, such that upon subjecting the device to a baked temperature of at least about 250° C. for at least about 360 hours, the threshold voltage of the floating-gate transistor shifts by no more than about 100 mV.

Dependencies are inferred from the claim text.