| 摘要 |
PURPOSE: A method for fabricating a MOS(metal oxide semiconductor) transistor is provided to simultaneously form two devices by one lithography process performed on the twice width of the device by forming two devices with respect to a deep trench in forming a MOS transistor with a vertical channel structure. CONSTITUTION: Impurities are injected to the upper surface of a semiconductor substrate(11) having a trench(12) for isolating an active region to form a drain(13) of a predetermined thickness. The drain and the substrate are selectively etched to protrude the drain and the substrate under the drain to both sidewalls of the trench. A sidewall is formed on both sidewalls of the protruding substrate under the drain. After a passivation layer is formed on the substrate except the sidewall and the drain, the sidewall is eliminated. By using the passivation layer as a mask, the substrate exposed by the removal of the sidewall is isotropically etched to form a gate body. A vertical channel(17) having a width narrower than that of the drain is formed on both sidewalls of the trench under the drain. The passivation layer is eliminated, and a gate oxide layer(18) is formed on the drain, the vertical channel and the semiconductor substrate. Impurities are injected to the substrate under the vertical channel to form a source(19). A gate(20) is formed in the gate body.
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