| Summary: | 碩士 === 國立臺灣師範大學 === 機電科技研究所 === 100 === As the dimension of metal-oxide-semiconductor field effect transistor (MOSFET) devices continues to scale down, the gate leakage current increases accordingly because the traditional gate oxide gradually approaches its physical limit. Therefore, high-K materials have been proposed to replace SiO2 in the literature.
Y2O3 is a promising high-K material because of its high dielectric constant (12-18), wide band gap (5.5 eV), stable thermal stability, chemical compatibility with Si and low lattice mismatch between Y2O3 and Si. However it is easy to form the interfacial layer because of the inter-diffusion between Y2O3 and Si. On the other hand, ZrO2 has also been reported to be a suitable material for gate dielectric layer though it starts to crystallize after high temperature process (ie. low crystallization temperature). Based on the above understanding, Zr is introduced into Y2O3 to form the gate dielectric layer, and ZrN is subsequently deposited to suppress the inter-diffusion. Finally, metal Ti is deposited to form the gate. In this work, electrical characteristics and physical properties have been studied for the samples after rapid thermal annealing at different temperatures.
The experimental results show that the Zr-incorporated Y2O3 thin film crystallizes and results in a rougher surface after a high temperature process. Moreover the ZrN layer can suppress inter-diffusion; however, the inter-diffusion still occurs if the ZrN layer is not thick enough.
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