Patent US 8,487,366

A device having thin-film transistor (TFT) metal-oxide-nitride-oxide-semiconductor (MONOS) or semiconductor-oxide-nitride-oxide-semiconductor (SONOS) memory cell structures includes a substrate, a dielectric layer on the substrate, and one or more source or drain regions being embedded in the dielectric layer. The dielectric layer is associated with a first surface. Each of the one or more source or drain regions includes an N+ polysilicon layer on a diffusion barrier layer which is on a conductive layer. The N+ polysilicon layer has a second surface substantially co-planar with the first surface. Additionally, the device includes a P− polysilicon layer overlying the co-planar surface, an oxide-nitride-oxide (ONO) layer overlying the P− polysilicon layer; and at least one control gate overlying the ONO layer. The control gate may be made of a metal layer or a P+ polysilicon layer.