| 摘要 |
The present invention provides a twin bit cell flash memory device and its fabricating method. The method is to first form a gate oxide layer on the surface of the silicon substrate followed by forming a polysilicon germanium (Si1-xGex, x=0.05~1.0) layer on the gate oxide layer. Thereafter, an ion implantation process is performed to form at least one insulating region in the polysilicon germanium layer for separating the polysilicon germanium layer into two isolated conductive regions and forming a twin bit cell structure. Then, a dielectric layer is formed on the polysilicon germanium layer and a photo-etching-process (PEP) is performed to etch portions of the dielectric layer and the polysilicon germanium layer for forming a floating gate of the twin bit cell flash memory. Finally, a control gate is formed over the floating gate.
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