METHOD FOR MANUFACTURING POWER ELEMENT HAVING TRENCH TYPE GATE ELECTRODE

摘要

PURPOSE: A method for manufacturing a power element having a trench type gate electrode is provided to prevent concentration of an electric field on edges of a trench gate electrode, by forming a thick oxide layer on the edges through making the edges gentle, to increase breakdown voltage of a power element, and to reduce leakage current of the power element. CONSTITUTION: A method for manufacturing a power element having a trench type gate electrode comprises the steps of: forming an insulator layer on a substrate; forming a sensitive film pattern on the insulator layer, and forming a first insulator layer pattern exposing the substrate by etching the insulator layer to make the sensitive film pattern into an etching mask; forming a first trench by etching the substrate; forming a second insulator layer pattern exposing the substrate in wider width than the first insulator layer pattern, by wet-etching side walls of the first insulator layer pattern; eliminating the sensitive film pattern; forming a main trench(27) by dry-etching the substrate of a lower part of the first trench, to make the second insulator layer pattern into an etching mask, and forming a parasitic trench in the substrate neighboring to an entrance of the main trench; removing the second insulator layer pattern; forming a thick gate oxide layer(29) on the parasitic trench, when forming the gate oxide layer on a surface of the main trench by performing a heat oxide process; burying a conductive layer composing a gate electrode in the trench; and forming a source and a drain(33,34) in the substrate neighboring to the trench.