| Summary: | 碩士 === 國立交通大學 === 電子工程系 === 88 === In recent years, there are large amounts of research and development of high K material for the reason of the scaling down and burst improvement of memory technology. The high K technology has reached a colossal success, just like BaSrTiO3 (BST, K=200), Ta2O5 (K=30~75), etc. But, there are several kind weaknesses of these developed high-K materials. One of them is the interfacial diffusion between the interface of the high K material and Si. For eliminating this effect, high K La2O3 gate dielectrics has been developed by using a process of direct thermal oxidization of deposited La. Using this high K material as the gate dielectric, MOSFETs and MOS capacitors have been fabricated. From the measurement of capacitance, the 33Å La2O3 has a K value of 27 that has an equivalent oxide thickness of 4.8 Å when considering the quantum correction. This high K is further evidenced from MOSFETs’ high current drive and high charge-to-breakdown comparable with SiO2 are obtained that demonstrates excellent reliability. Good dielectric integrity is evidenced from the low leakage current density of 0.06A/cm2 at -1V, high effective breakdown field of 13.5 MV/cm, low interface density of 3x1010ev-1cm-2. The achieved low equivalent oxide thickness is due to the high thermodynamic stability on Si and also stable for hydrogen annealing up to 550ºC.
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