METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICES

摘要

PURPOSE: A fabrication method of semiconductor devices having different threshold voltage is provided to simplify manufacturing process and improve an yield by using an SPG(selective poly-silicon growing) without additional well processes. CONSTITUTION: The method comprises the steps of forming an isolation oxide(12) on a semiconductor substrate(10); forming an N-well(16) and a P-well(18) in the substrate; performing an N-channel ion implantation in a portion of the substrate; forming a sacrificial oxide(14) on the resultant structure; removing the sacrificial oxide(14) on the region to be form a device having different threshold voltage(Vt); forming an SPG layer(24) on the exposed substrate; removing the remained sacrificial oxide(14); forming a gate oxide(26) and a gate electrode(28); and forming NMOS transistors having a low and a high threshold voltage(Vt) and a PMOS transistor on the SPG layer(24) by ion-implanting.