Abstract: The present invention discloses a method for fabricating a non-volatile memory structure from a single layer of polysilicon in a semiconductor substrate, wherein the semiconductor substrate with two active areas, first and second, are divided by isolation regions. In accordance with this method, a doped buried layer is formed in the first active area. Then, a first floating gate is formed on the buried layer and a second floating gate is formed on the second active area from the single layer of polysilicon. Next, two doped regions are formed at opposite sides of the second floating gate in the second active areas. Finally, a floating gate connection line is employed to connect the first and second floating gate for making sure that the two floating gates are in the same potential.

Abstract: The present invention discloses a single poly non-volatile memory structure includeing a semiconductor substrate with two active areas divided by isolation regions. A control gate doped with N-type impurities is embedded in the first active area, and a first floating gate is formed thereon. A second floating gate is formed on the substrate of the second active area, and two doped regions are implanted at opposite sides of the second active areas in the substrate. A floating gate line is employed to connect the first and second floating gate for making sure that the two floating gates are in the same potential. When the control gate is biased to a voltage level, the voltage level would be coupled to the first floating gate so as to keep the second floating gate in the same potential with the first floating gate.

Abstract: The present invention discloses a single poly non-volatile memory structure including a semiconductor substrate with two active areas divided by isolation regions. A control gate doped with N-type impurities is embedded in the first active area, and a first floating gate is formed thereon. A second floating gate is formed on the substrate of the second active area, and two doped regions are implanted at opposite sides of the second active areas in the substrate. A floating gate line is employed to connect the first and second floating gate for making sure that the two floating gates are in the same potential. When the control gate is biased to a voltage level, the voltage level would be coupled to the first floating gate so as to keep the second floating gate in the same potential with the first floating gate. While one of the doped regions is biased to a voltage level, electrons would eject from the other doped region and trapped in the floating gates, thereby preserving information in this memory structure.

Abstract: A method for forming a concave bottom oxide layer in a trench, comprising: providing a semiconductor substrate; forming a pad oxide layer on the semiconductor substrate; forming a silicon nitride layer on the pad oxide layer; etching the silicon nitride layer, the pad oxide layer and the semiconductor substrate to form the trench in the semiconductor substrate; depositing a silicon oxide layer to refill into the trench and cover on the silicon nitride layer, wherein the silicon oxide layer has overhang portions at corners of the trench; anisotropically etching the silicon oxide layer to form a concave bottom oxide layer in the trench; etching the silicon oxide layer to remove the silicon oxide layer on the silicon nitride layer and the sidewalls of the trench; removing the silicon nitride layer and the pad oxide layer.