High-performance poly-Si TFTs of top-gate with high-κ metal-gate combine the laser annealed channel and glass substrate

We demonstrate high-performance low-temperature poly-Si thin film transistors (LTPS-TFTs) with a TaN/Hf -based top-gate-stack and combine the channel film by laser annealing and glass substrate (glass substrate high- κ metal-gate thin film transistor, called GSHM-TFTs). The GSHM-TFTs of n-channel (called GSHM-NTFTs) exhibit a very low threshold voltage, low supply voltage (∼2 V), steep subthreshold swing (S.S.) ∼95 mV/dec, and high I_ON / I_OFF ratio > 107. In contrast, GSHM-TFTs of p-channel (called GSHM-PTFTs) exhibit an S.S. ∼154 mV/dec and an I _ON / I_OFF ratio even higher than 108. Furthermore, the driving currents are also enhanced in GSHM-TFTs. These significant improvements are due to the combination of laser annealed channel film and the very high gate-capacitance density provided by Hf O₂ gate dielectrics with the effective oxide thickness of 14 nm.