| 摘要 |
PURPOSE: A method for fabricating a thin film transistor of bottom gate type is provided to enhance current-driving performance. CONSTITUTION: In a static random access memory(SRAM), the fabrication of a thin film transistor(TFT) of bottom gate type begins with the provision of a silicon substrate having an access transistor and a driver transistor thereon. Next, after an interlayer dielectric(20) is formed on the substrate, a gate electrode(21) and a gate oxide(22) are successively formed on the interlayer dielectric(20). Then, a first polysilicon layer(23) for channel is deposited on overall surfaces, and an ion implantation for lightly doped offset(LDO) follows. Next, a photoresist pattern(24) is formed to overlap with predetermined both a channel region and an LDO region. Then, a second polysilicon layer(25) is deposited and another ion implantation for source/drain follows. The photoresist pattern(24) is then removed by lift-off. As a result, both polysilicon layers(23,25) remain on the source/drain and source overlap regions, whereas the only polysilicon layer(23) remains on the channel and LDO regions.
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