Passivation-Induced Subthreshold Kink Effect of Ultrathin-Oxide Low-Temperature Polycrystalline Silicon Thin Film Transistors

Polycrystalline silicon thin-film transistors (poly-Si TFTs) with an ultrathin electron cyclotron resonance plasma-oxidized gate oxide have been fabricated. These ultrathin gate oxide poly-Si TFTs demonstrate better gate controllability and short-channel effect suppression, as compared with conventional thick-gate oxide poly-Si TFTs. A subthreshold kink effect has been observed in these ultrathin gate oxide poly-Si TFTs after NH₃ plasma treatment for the first time. The ultrathin oxide will limit the diffusion of plasma radicals, resulting in plasma radical pileup along the channel width, causing this subthreshold kink effect. The kink effect will be less significant in devices with a narrow channel width as the current flow associated with the corners of the device will dominate over the flat-plate region.