Solution-Processable LaZrOx/SiO2 Gate Dielectric at Low Temperature of 180 掳C for High-Performance Metal Oxide Field-Effect Transistors
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- 作者：So Yeon Je ; Byeong-Geun Son ; Hyun-Gwan Kim ; Man-Young Park ; Lee-Mi Do ; Rino Choi ; Jae Kyeong Jeong
- 刊名：ACS Applied Materials & Interfaces
- 出版年：2014
- 出版时间：November 12, 2014
- 年：2014
- 卷：6
- 期：21
- 页码：18693-18703
- 全文大小：665K
- ISSN：1944-8252
文摘
Although solution-processable high-k inorganic dielectrics have been implemented as a gate insulator for high-performance, low-cost transition metal oxide field-effect transistors (FETs), the high-temperature annealing (>300 掳C) required to achieve acceptable insulating properties still limits the facile realization of flexible electronics. This study reports that the addition of a 2-dimetylamino-1-propanol (DMAPO) catalyst to a perhydropolysilazane (PHPS) solution enables a significant reduction of the curing temperature for the resulting SiO2 dielectrics to as low as 180 掳C. The hydrolysis and condensation of the as-spun PHPS film under humidity conditions were enhanced greatly by the presence of DMAPO, even at extremely low curing temperatures, which allowed a smooth surface (roughness of 0.31 nm) and acceptable leakage characteristics (1.8 脳 10鈥? A/cm2 at an electric field of 1MV/cm) of the resulting SiO2 dielectric films. Although the resulting indium zinc oxide (IZO) FETs exhibited an apparent high mobility of 261.6 cm2/(V s), they suffered from a low on/off current (ION/OFF) ratio and large hysteresis due to the hygroscopic property of silazane-derived SiO2 film. The ION/OFF value and hysteresis instability of IZO FETs was improved by capping the high-k LaZrOx dielectric on a solution-processed SiO2 film via sol鈥揼el processing at a low temperature of 180 掳C while maintaining a high mobility of 24.8 cm2/(V s). This superior performance of the IZO FETs with a spin-coated LaZrOx/SiO2 bilayer gate insulator can be attributed to the efficient intercalation of the 5s orbital of In3+ ion in the IZO channel, the good interface matching of IZO/LaZrOx and the carrier blocking ability of PHPS-derived SiO2 dielectric film. Therefore, the solution-processable LaZrOx/SiO2 stack can be a promising candidate as a gate dielectric for low-temperature, high-performance, and low-cost flexible metal oxide FETs.