A novel four-mask-step low-temperature polysilicon thin-film transistor with self-aligned raised source/drain (SARSD)

In this letter, a novel structure of polycrystalline-silicon thin-film transistors (TFTs) with self-aligned raised source/drain (SARSD) and a thin channel has been developed and investigated. In the proposed structure, a thick SD and a thin active region could be achieved with only four mask steps, which are less than that in conventional raised SD TFTs. The proposed SARSD TFT has a higher ON-state current and a lower OFF-state leakage current. Moreover, the ON/OFF current ratio of the proposed SARSD TFT is also higher than that of a conventional coplanar TFT.