| 摘要 |
PURPOSE: A manufacturing method of a polysilicon thin film transistor having a lightly doped drain(LDD) structure is provided to reduce steps of process and to manufacture a polysilicon thin film transistor by implantation of a low energy ion and a low heat treatment. CONSTITUTION: After a buffer layer is formed on a substrate(10), a polysilicon pattern(20) and a gate oxide layer(30) are successively formed on the substrate(10). A gate electrode(40) is then formed on the gate oxide layer(30), and n-type dopant is lightly doped into the polysilicon pattern(20) to define LDD regions(230). Next, a dielectric layer(60) is deposited and contact holes(610) are formed in both layers(30,60) to expose a portion of the LDD regions(230). High-concentrated n-type dopant is further doped by using the dielectric layer(60) as a mask, and actuated by heat treatment, so that a source region(210) and a drain region(220) are defined. After that, a source electrode, a drain electrode, and a protective layer are formed. Finally, a pixel electrode is formed to contact with the drain electrode.
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