| 摘要 |
PURPOSE: A method for manufacturing a double-diffused metal oxide semiconductor(DMOS) filed effect transistor(FET) is provided to control a threshold voltage while forming a desired short channel length, without deteriorating reliability. CONSTITUTION: In an upper constant region of a semiconductor substrate(100) of a first conductivity type is formed a well region(120) of a second conductivity type opposite to the first conductivity type. A first mask layer pattern exposing a first region in the well region and a second region adjacent to the first region is used as an injection mask to inject impurity ions of the first conductivity type. Next, a first density of impurity ions of the second conductivity type of which a diffusion speed is slower than that of the impurity ions of the first conductivity type, is injected by using the first mask layer pattern as an ion-injection mask. Impurity ions of the first and second conductivity types injected into the first and second regions are simultaneously drive-in diffused. Then, impurity ions for controlling a threshold voltage on the surface of the second region are injected. By using the mask layer pattern exposing a part of the first region, a second density of impurity ions of the second conductivity type are injected and drive-in diffused, in which the second density is higher than the first density.
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