SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

摘要

PURPOSE: A method for manufacturing a semiconductor device is to provide a transistor having a gate length smaller than a critical dimension of a gate mask, and to guarantee a reduced gate channel length margin by forming a channel of a round shape. CONSTITUTION: A first and a second insulating layers are evaporated on a substrate(31). A partial region of the first and the second insulating layers are etched to form a trench on the substrate. A third insulating layer is formed on the surface of the trench in the substrate and on an inner surface of the first and the second insulating layers. A first sidewall spacer is formed on an inner surface of the third insulating layer. A thermal oxidation layer is formed on the substrate between the first sidewall spacer. The first sidewall spacer is eliminated. First impurity ions are injected into the substrate by using the thermal oxidation layer. A second sidewall spacer(37) is formed on an inner surface of the third insulating layer on both sides of the thermal oxidation layer. The thermal oxidation layer is eliminated to expose the substrate of a round shape. A gate insulating layer(38) is formed on the exposed substrate. A gate electrode(39) is formed on the gate insulating layer between the second sidewall spacer. After the second insulating layer is eliminated, a second impurity region is formed in the substrate on both sides of the second sidewall spacer and third insulating layer excluding the gate electrode.