Patent ID: 7473601

Claim:
A Method of fabricating a flash memory device using a sidewall process comprising: depositing an insulating layer on a substrate; forming at least one trench in the insulating layer by etching the insulating layer; depositing a first polysilicon layer over and in said at least one trench; forming floating gates on side surfaces of the insulating layer by etching the first polysilicon layer; removing the insulating layer; forming a first photoresist pattern over the substrate; forming first source/drain regions in the substrate adjacent to the floating gate by a first ion implantation using the first photoresist pattern as a mask; removing the first photoresist pattern depositing an oxide-nitride-oxide (ONO) layer over the substrate; depositing a second polysilicon layer over the ONO layer; forming a control gate and at least one select gate by etching the second polysilicon layer; forming a second photoresist pattern over the control gate and the select gate; and then forming second source/drain regions in the substrate adjacent to the select gate by a second ion implantation using the second photoresist pattern as a mask.