1.Radial Interference Contrast in in-situ SEM Observation of Metal Oxide Semiconductor Film Crystallization
1.Radial Interference Contrast in in-situ SEM Observation of Metal Oxide Semiconductor Film Crystallization
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1.金属氧化物半导体薄膜结晶的原位SEM观察中的径向干涉对比
DOI：
10.1017/s1431927617008224
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发表时间：
2017
影响因子：
2.8
通讯作者：
Toshihide Nabatame,
中科院分区：
文献类型：
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作者：
Kunji Shigeto;Takio Kizu;Kazuhito Tsukagoshi;Toshihide Nabatame,
基于透明非晶氧化物半导体薄膜的薄膜晶体管（TFT）对于下一代平板显示器的高速开关操作有着强烈的需求。非晶InGaZnO（a-InGaZnO）TFT已被认为是目前最有前途的候选器件[1]。虽然a-InGaZnO TFT已部分用于商业显示器中，但对于由氧空位（Vo）[2]引起的稳定性问题存在争议，氧空位在膜中产生过量的电荷载流子。作为寻找有效Vo抑制剂的指标，发现添加剂原子与氧之间的键离解能是选择添加剂进入氧化物膜基质的合理参数[3]。在具有高键离解能的添加剂中，Si或W有效地抑制了InOx基TFT的不稳定性问题[4]。为了更好地理解添加剂原子在氧化膜中的作用，在这里，我们通过原位SEM观察表征了氧化铟硅（InSiO）和氧化铟钨（InWO）的结晶动力学。结果表明，只有InSiO中才能获得独特的背散射电子（BSE）图像，这可能是由于晶面内的电子干涉所致。InSiO的溅射靶由97 wt.%含3 wt.%的In 2 O3二氧化硅。InWO靶由90 wt.%含10 wt.%的In 2 O3 WO3。相应的Si和W的原子比分别为2.6和2.4，从而表明在两种膜中的可比的添加剂比例。利用加热子阶段Gatan Murano和肖特基SEM Hitachi SU 5000的组合进行原位SEM观察。这种组合系统使我们能够获得结晶动态图像沿着一个精确固定的观察区域。
Thin-Film Transistors (TFTs) based on transparent amorphous-oxide semiconducting films are in strong demand for high-speed switching operations in next-generation flat panel displays. Amorphous InGaZnO (a-InGaZnO) TFTs have been recognized as the most promising candidate at the moment [1]. Although the a-InGaZnO TFT has been partially used in commercial displays, there is controversy on the stability issues caused by oxygen vacancies (Vo)[2], which generate excess charge carriers in the films. As an index to seek an effective Vo suppressant, the bond dissociation energy between additive atoms and oxygen is found to be a reasonable parameter for selecting the additive into the oxide film matrix [3]. Among the additives with high bond dissociation energy, Si or W effectively suppresses the instability issue of InOx-based TFTs [4]. To better understand the role of additive atoms in the oxide film, here, we characterized crystallization dynamics of indium silicon oxide (InSiO) and indium tungsten oxide (InWO) by in-situ SEM observation. Results show that unique backscattered electron (BSE) images were obtained only in InSiO, possibly due to electron interference in the crystal plane.Amorphous films of with a thickness of 30nm were prepared on sapphire substrates by means of DC magnetron sputtering at room temperature. Sputtering target of InSiO was composed of 97wt.% In2O3 with 3wt.% SiO2. The InWO target was composed of 90wt.% In2O3 with 10wt.% WO3. Corresponding atomic ratio of Si and W are 2.6 and 2.4 respectively, thus indicating comparable additive ratios in the two films. In-situ SEM observations were performed utilizing the combination of heating sub-stage Gatan Murano and Schottky SEM Hitachi SU5000. This combined system allows us to obtain images of crystallization dynamically along a precisely fixed observation area.