Effect of Nitridation of Bottom Interlayer in FeFETs With the TiN/Al } O } /Hf } Zr } O } /Bottom Interlayer/Si Substrate Structure

• Published in: IEEE transactions on electron devices pp. 1 - 7
• Main Authors: Yang, Jia, Han, Runhao, Hu, Tao, Dai, Saifei, Shao, Xianzhou, Sun, Xiaoqing, Chai, Junshuai, Xu, Hao, Han, Kai, Wang, Yanrong, Zhang, Jing, Wang, Xiaolei, Wang, Wenwu, Ye, Tianchun
• Format: Journal Article
• Language: English
• Published: IEEE 15-10-2024
• Subjects: Charge trapping; ferroelectric field-effect transistor (FeFET); interlayer; memory window (MW); nitridation
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2024.3473889

In this work, we investigate the effect of nitridation of the bottom interlayer in HfO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula>-based ferroelectric silicon channel field-effect transistors (HfO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> Si-FeFETs) with the TiN/top interlayer/ferroelectric/bottom interlayer/Si substrate (MIFIS) structure. We find that the SiON bottom interlayer induces a smaller memory window (MW) compared with the case of SiO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> as a bottom interlayer in the MIFIS structure. The origin is the reduced barrier height at the bottom interlayer induced by the positive charges in the SiON layer, which makes the charges injected from the metal gate cannot remain after erasing operation. However, the SiON bottom interface in the MIFIS structure shows higher endurance and stable retention than the SiO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> bottom interface. Thus, for the ferroelectric field-effect transistor (FeFET) gate stacks with a top interlayer (MIFIS structure), the SiO<inline-formula> <tex-math notation="LaTeX">_{\text{2}}</tex-math> </inline-formula> is more suitable than the SiON as a bottom interlayer to realize larger MW, while the SiON bottom interlayer can improve retention and endurance at the expense of MW.