| Summary: | 碩士 === 國立臺灣大學 === 電子工程學研究所 === 94 === The Au nanocrystal charge storage device by using High-K material as tunneling layer will be investigated in both C-V and Retention measurement to realize how the charge is programmed, erased and leaked. The tunneling layer material, such as HfO2 and HfSiO2, will be examined by XRD, IV, and CV measurement after different temperature annealing. The crystallization phenomenon is observed in HfO2 at high temperature. This phenomenon will decrease the performance of our device. In order to avoid crystallization, we use chemical redundant deposition to fabricate Au nano-dots. Because this process can be done in room temperature, we can keep HfO2 away from high temperature process. Owing to the high permittivity, HfO2 can be thicker than SiO2 in the same equivalent oxide thickness (EOT) and reduce the leakage current from Au nano-dots to silicon substrate. Thus, the retention of device by using HfO2 as tunneling layer is two times better than that by using SiO2 as tunneling layer. Another way to avoid crystallization is to change tunneling layer from HfO2 to HfSiO2. The crystallization phenomenon is not observed in HfSiO2 after high temperature annealing. At last, we are able to fabricate different density of Au dots in devices by using HfSiO2 as tunneling layer by controlling the deposition time. In this way, we can examine the relationship between the stored charge and the density of Au nano-dots.
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