| 摘要 |
PURPOSE: A method for making a semiconductor device is provided to increase a distance between a well area and a high-density impurity area by using a recess PBL(polybuffered LOCOS) isolation process, and enhance a punch-through characteristic. CONSTITUTION: In a method for making a full CMOS(FCMOS) SRAM cell, a pad oxide layer(46), a poly-buffer layer, and a nitride layer are formed on a semiconductor substrate. The first photoresist layer is formed on the nitride layer. A pad oxide layer, a poly-buffer layer, and a nitride layer are formed by using the first photoresist layer as a mask, thereby exposing a substrate on which a field oxide layer(46) is to be formed. The first photoresist layer is removed, and the second photoresist layer is formed. The substrate is etched by using the second photoresist layer as a mask, thereby forming a recess. The second photoresist layer is removed. A field oxide layer is formed on the exposed substrate through a recess LOCOS process. P-well(47) and N-well(48) are formed in the substrate. A gate of NMOS transistor and a high-density impurity area are formed on the substrate having the P-well thereon. A gate of PMOS transistor and a high-density impurity area are formed on the substrate having the N-well thereon.
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