METHOD FOR MANUFACTURING TRANSISTORS

摘要

PURPOSE: A fabrication method of a transistor is provided to reduce a reverse short channel effect and improve a doping depth of channel regions by performing two-step punch through stop implantation. CONSTITUTION: The method comprises the steps of: forming an oxidation preventing layer(12) opened a field region on a semiconductor substrate(11); forming a first punch-through stop implantation region(13) in the semiconductor substrate(11) of the field region by performing a first punch-through stop implantation process; forming a field oxide layer(14) in the semiconductor substrate of the field region by oxidation process; removing the oxidation preventing layer(12); forming a second punch-through stop implantation region(15) in the semiconductor substrate(11) of a channel active region by performing a second punch-through stop implantation process; and forming a source and drain junctions(19) of an LDD structure by performing a threshold voltage implantation process. The second punch-through stop implantation has a high implantation energy compared to the threshold voltage implantation.