3次元積層デバイス開発為の分子動力学計算によるプラズマエッチング反応の解析

3D NAND闪存技术已经成为任何需要数据存储的平台的主要解决方案。其存储容量取决于沉积在硅衬底上的二氧化硅（SiO2）和氮化硅（SiN）交替堆叠薄膜（称为ONO）的数量。在堆叠的薄膜中蚀刻具有高宽高比（AR）和直轮廓的孔通道，形成存储单元阵列。然而，随着AR的增加，保持直线轮廓变得更加困难。因此，高宽高比（HAR）蚀刻一直是具有更大存储容量的3D NAND器件的障碍。在本研究中，进行了实验和模拟，以了解3D NAND存储器件制造中的HAR蚀刻过程。实验中，在硅晶片上沉积SiO2、SiN和ONO堆叠薄膜，并使用Ar和CF3离子束系统进行蚀刻。计算了蚀刻率和蚀刻率，并用x射线光电子能谱（XPS）对膜进行了表征。在模拟过程中，对Ar、Cl和CF3离子蚀刻SiO2、SiN和ONO的过程进行了分子动力学（MD）模拟。将模拟所得的蚀刻产率与实验所得的蚀刻产率进行了比较，其中获得了相对较好的一致性。因此，一些研究成果已在各种国内和国际会议上发表。该研究还被总结成一篇论文，并发表在3篇科学论文中。

The 3D NAND flash memory technology has been the primary solution for any platforms requiring data storage. Its memory capacity is dictated by the number of alternating silicon dioxide (SiO2) and silicon nitride (SiN) stacked films (referred to as ONO) deposited on a Si substrate. Hole channels with a high aspect ratio (AR) and straight profiles are etched through the stacked films to form the memory cell arrays. However, maintaining a straight profile becomes more difficult as the AR increases. As such, high aspect ratio (HAR) etching has been the roadblock for 3D NAND devices with larger storage capacity. In this research, experiments, and simulations had been performed to understand the HAR etching process in the fabrication of 3D NAND memory devices. For the experiment, SiO2, SiN, and ONO stacked films deposited on Si wafers were etched with Ar and CF3 ions using the mass-selected ion beam system. The etch yields and etch rates were calculated, and the films were characterized by X-ray photoelectron spectroscopy (XPS). For the simulation, molecular dynamics (MD) simulations of the etching of SiO2, SiN, and ONO by Ar, Cl, and CF3 ions were done. The etch yields from the simulations were compared to the etch yields from the experiments wherein a relatively good agreement was attained. As such, some of the results of the research have been presented at various domestic and international conferences. The research has also been summarized in a dissertation and published in 3 scientific papers.