Using thin undoped teos with bpteos ild or bpteos ild alone to improve charge loss and contact resistance in multi bit memory devices

Abstract

The present invention facilitates dual bit memory devices and operation of dual bit memory device by providing systems and methods that employ a relatively thin undoped TEOS liner during fabrication, instead of a relatively thick TEOS layer that is conventionally used. Employment of the relatively thin liner facilitates dual bit memory device operation by mitigating charge loss and contact resistance while providing protection against unwanted dopant diffusion. The present invention includes utilizing a relatively thin undoped TEOS liner that is formed on wordlines and portions of a charge trapping dielectric layer. The relatively thin undoped TEOS liner is formed with a thickness of less than about 400 Angstroms so that contact resistance and charge loss are improved and yet providing suitable protection for operation of the device. Additionally, the present invention includes foregoing with an undoped TEOS liner altogether.