Enhanced electrical performance and reliability of Ti-IGZO thin-film transistors with Hf1-xAlxO gate dielectrics
Enhanced electrical performance and reliability of Ti-IGZO thin-film transistors with Hf1-xAlxO gate dielectrics
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DOI：
10.7567/1347-4065/ab6590
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发表时间：
2019-09
影响因子：
1.5
通讯作者：
B. You;Shui-Jinn Wang;R. Ko;Jhong-Han Wu;Chen-En Lin
中科院分区：
文献类型：
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作者：
B. You;Shui-Jinn Wang;R. Ko;Jhong-Han Wu;Chen-En Lin
为了提高器件的性能和可靠性，提出了一种具有Ti-IGZO沟道层和Hf1-xAlxO栅介质层的薄膜晶体管。实验结果表明，在基于HfO2/IGZO、Hf1-xAlxO/IGZO和Hf1-xAlxO/Ti-IGZO栅介质/沟道结构的三种TFT中，Hf0.88Al0.12O/Ti(2.0%)-IGZO TFT的亚阈值摆幅为86 mV/dec−1，场效应迁移率为28.63cm2∙V−1∙S−1，通断电流比为3.26×108。与HfO2/IGZOTFT的0.45V和0.612 V/−0.507 V/−0.657 V相比，1000V S正/负栅偏压/白光照射下的阈值电压漂移为0.45 V和0.612 V/−0.507 V/−0.657 V。这些改进是由于在IGZO沟道中掺入了钛，从而降低了缺陷密度，同时向HfO2中添加Al改善了表面粗糙度，以抑制应力测试期间的表面散射和电荷捕获。
A thin-film transistor (TFT) with a Ti-IGZO channel layer and Hf1-xAlxO gate dielectric is proposed to improve the performance and reliability of the device. The experimental results show that in three types of TFTs based on HfO2/IGZO, Hf1-xAlxO/IGZO and Hf1-xAlxO/Ti-IGZO gate dielectric/channel structures, the Hf0.88Al0.12O/Ti (2.0%)-IGZO TFT exhibits the best device performance with the subthreshold swing of 86 mV dec−1, field-effect mobility of 28.63 cm2∙V−1∙s−1 and on/off current ratio of 3.26 × 108. In particular, it shows a hysteresis voltage as low as 0.02 V and a threshold voltage shift after 1000 s positive/negative gate bias stress/white light illumination of 0.134 V/−0.089 V/−0.195 V, compared with 0.45 V and 0.612 V/−0.507 V/−0.657 V of the HfO2/IGZO TFT. These improvements are due to the incorporation of Ti into the IGZO channel, which reduces defect density, while adding Al to HfO2 improves surface roughness to inhibit surface scattering and charge capture during stress testing.