| 摘要 |
<p>A method for manufacturing a flash memory device is provided to protect a gate oxide layer of a low-voltage transistor and to prevent thinning of the gate oxide layer by using a buffer poly. A gate oxide layer(112) is formed on a substrate(100) having a cell region and a peripheral region. A buffer poly(116) is formed on the gate oxide layer for protecting the gate oxide layer. A hard mask pattern including an oxide layer and a nitride layer is formed on the resultant structure. The buffer poly is etched to expose the gate oxide layer using the hard mask pattern. The exposed gate oxide layer is etched, and a trench is formed in the substrate. A sidewall oxide layer(122) is then formed at sidewalls of the trench by performing sidewall oxidation processing.</p> |
