双栅非晶InGaZnO非易失性薄膜晶体管存储器的研究

Amorphous InGaZnO （a-IGZO）cannot form an inversion state, and this causes the a-IGZO thin-film transistor memory (TFTM) to display poor erase efficiency and small memory window. To solve this issue, a dual-gate TFTM consisting of top gate/blocking layer/charge-trapping layer/tunneling layer/bottom oxide/bottom gate is proposed. This dual-gate TFTM utilizes the top-gate-type TFTM and the bottom-gate-type thin film transistor (TFT) to perform program/erase and read operation, respectively. Consequently, the memory window of the top-gate-type TFTM can be amplified by using bottom-gate-type TFT for read operation and the read disturb can be also removed, thus improving the memory performance. Besides, the separation of program/erase and read operation makes other key parameters (e.g. mobility, sub-threshold swing) of the TFTM mainly determined by the bottom-gate-type TFT, and thus is desirable to improve the work speed..This work aims at realizing the dual-gate TFTM. Based on the features of InGaZnO material and process, we will study the optimal processes to fabricate the device and also explore the optimal structural parameters of the dielectric films for the device. Based on the above progress, the device prototype will be developed. Combined with the advantages of dual-gate structure mentioned above, the appropriate high-k materials and processes are expected to fully prompt the TFTM performance. This work contributes to push the development of System-on-Panel technology.

非晶InGaZnO难以反型的特点造成当前薄膜晶体管存储器（TFTM）擦除效率低及存储窗口小等问题，为此，提出一种双栅结构的TFTM，自上而下为：顶栅/阻挡层/俘获层/隧穿层/沟道层/底栅氧化层/底栅。该双栅TFTM分别利用顶栅TFTM和底栅薄膜晶体管（TFT）进行存储器的“编程/擦除”和“读”操作：利用底栅TFT进行“读”操作可实现对顶栅TFTM存储窗口的放大，并消除“读”操作对俘获在顶栅TFTM中的电荷的干扰，提升了器件存储性能；“编程/擦除”和“读”操作分离还使TFTM的迁移率、亚阈值摆幅等器件性能可达到底栅TFT的水平，提高了器件工作速度。.本项目以双栅TFTM为目标，根据InGaZnO材料和工艺特点，探索制备器件的最佳工艺和条件及相关介质的最佳结构参数，研制出器件原型。结合双栅TFTM结构的上述优势，并发展出合适的高k介质材料和工艺，全面提升TFTM性能，促进“系统面统”技术发展。

IGZO具有迁移率高、均一性好、漏电小、制备工艺简单等优点，因此，被视为发展下一代平板显示的理想沟道材料。为满足“系统面板”的发展需求，项目针对构建“面板系统”的IGZO基非易失性存储器和薄膜晶体管两类基础性器件开展系统研究，通过三年多的努力，实现了预期目标：开发了高性能的电荷存储层材料和栅介质层材料，获得了制备上述材料的最佳工艺和条件；获得了源/漏接触电阻对IGZO基器件尺寸缩小能力的影响规律，掌握减小接触电阻的方法及其相关微观作用机制；揭示了湿气等对IGZO基器件性能（尤其是稳定性能）的影响和微观作用机制，获得了改善器件性能（尤其是稳定性能）的方法和技术；研制了双栅型存储器，掌握了双栅型存储器的操作模式和电学操作方法，证实了其对器件性能提升的可行性和有效性。. 基于上述成果，项目组目前共在IEEE刊物和Applied Physics Letters期刊上发表SCI论文7篇（包括IEEE Electron Device Letters 3篇、IEEE Transactions on Electron Devices 2篇、Applied Physics Letters 1篇）、EI论文2篇，受邀在IEEE会议上做邀请报告1次。目前共申请中国发明专利6项，其中3项已授权。此外，在项目支持下，项目负责人先后获江苏省六大人才高峰（2018年）、江苏省青蓝工程中青年学术带头人（2019年）等计划，并获江苏省优秀青年基金资助（2018年）。