Method of forming transistor using the step shallow trench isolation profile in a nand flash memory device

摘要

invention step STI (Shallow Trench Isolation) profile (Profile) using the NAND flash memory device of the transistor relates to a method of forming , after forming a spacer on both side walls STI , to carry out step by forming a step STI STI etch profile , as well as to secure a wide active width , to improve the transistor performance of the cell area and the peripheral area there . As a result , the chip size is reduced to reduce the cost (cost), to improve the cell current and improve program speed . And after forming the STI step profile , by an annealing process , it is possible to prevent the thinning (thinning) is generated in the oxide film in the vicinity of a corner (corner) of the oxidation process step STI edge (edge).