Ultra-thin elevated channel poly-Si TFT technology for fully-integrated AMLCD system on glass

A novel low temperature poly-Si (LTPS) TFT technology called the ultra-thin elevated channel TFT (UT-ECTFT) technology is proposed. The devices fabric ated using this tech nology have an ultra-thin channel region (300 Angstrom ) and a thick drain/source region (3000 Angstrom). The ultra-thin channel r egion is connected to the heavily doped thick drain/source region through a lightly doped overlapped region. The ultra-thin channel region is used to obtain a low grain-boundary trap density in the channel, and the overlapped lightly doped region provides an effective way for electric field spreadin g at the drain, thereby reduces the electric field there significantly. Wit h the low grain-boundary trap density and low drain electric field, excelle nt current saturation characteristics and high drain breakdown voltage are obtained in the UT-ECTFT, Moreover, this technology provides complementary LTPS TFT's with more than two times increase in on-current, 3.5 times reduc tion in off-current compared to conventional thick channel LTPS TFT's.