The Institute of Microelectronics has made important progress in new nanometer gate-all-around CMOS technology and device technology
As integrated circuit manufacturing technology continues to evolve, stacked nanosheets GAA FETs will replace traditional fin transistors ( FinFETs ) at nodes below 3 nanometers , further promoting the development of the semiconductor industry. However, in the face of the demand for large-scale manufacturing, GAA transistor technology still needs to break through key challenges such as serious mismatch in operating current (
I on ) between N -type and P -type devices and difficulty in regulating threshold voltage (
V th ). It is also important for nanosheet channel materials and High- κ metal gate materials put forward more technological innovation requirements. Therefore, device structure innovation for GAA transistors has become an important direction for future logic device process research.
Recently, the team of researcher Yin Huaxiang from the Leading Center of the Institute of Microelectronics adjusted the Ge content of the bottom SiGe layer in the epitaxial SiGe/Si stack on the bulk silicon substrate based on the mainstream GAA transistor manufacturing process , and used nanometer-scale high-density silicon in the back gate channel. Using SiGe layer etching technology, a GAA device ( FishboneFET ) with a channel structure similar to a fishbone was designed and prepared for the first time . Due to the introduction of additional strained SiGe nano-fin structures between traditional stacked Si nanosheets, the channel conductive area in GAA devices is greatly increased and the driving performance of P- type devices is improved under the same planar projected area . Compared with the same type of tree -like GAA device ( TreeFET ), the designed FishboneFET further improves the electrical performance mismatch problem between N -type and P -type devices, and uses a single work function metal gate material to achieve CMOS- oriented The threshold regulation of the device solves the key challenge of FishboneFET transistor in CMOS integration. Based on the above innovative technologies, the research team successfully developed CMOS FishboneFET and TreeFET devices that are compatible with mainstream GAA device processes for the first time in the world , achieving a high N/PFET device current switching ratio and a more balanced N- type under a single work function metal gate. Matching the driving performance of P -type GAA devices, it was found that N -type TreeFET and FishboneFET have more advantages in suppressing the drain-induced barrier lowering ( DIBL ) effect of short-channel devices, and TreeFET has a lower DIBL effect than FishboneFET . The research team proposed the valence band compensation theory in strained SiGe nano-fin , successfully explained the special electrical effects in the new structure, and established a key technology path for the introduction of new GAA transistors into high-performance CMOS integrated circuit applications.
The results were recently published in the Institute of Electrical and Electronics Engineers Electronic Devices Letters ( IEEE Electron Device Letters, Vol. 44, No. 9, 1396 (2023), DOI: 10.1109/LED.2023.3294545 ), and became the " Editors' Picks " recommended and judged by the editor-in-chief of EDL , Ph.D. of the Leading Center of the Institute of Microelectronics Cao Lei is the first author of this article. Researcher Yin Huaxiang and young researcher Zhang Qingzhu are the corresponding authors of this article. This research was supported by the Strategic Priority Project ( Category A ) of the Chinese Academy of Sciences, the National Natural Science Foundation of China and other projects.
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