Monolithic 3-D Self-Aligned Heterogeneous Nanosheet Channel Complementary FETs With Matched VT by Band Alignments of Individual Channels

• Published in: IEEE transactions on electron devices Vol. 71; no. 5; pp. 3383 - 3389
• Main Authors: Hsieh, Wan-Hsuan, Tu, Chien-Te, Chen, Yu-Rui, Huang, Bo-Wei, Chen, Wei-Jen, Liu, Yi-Chun, Cheng, Chun-Yi, Chou, Hung-Chun, Liu, C. W.
• Format: Journal Article
• Language: English
• Published: IEEE 01.05.2024
• Subjects: Chemical vapor deposition; complementary FET (CFET); Epitaxial growth; Field effect transistors; Germanium; Germanium silicon alloys; GeSi; GeSn; heterogeneous channels; high-κ gate stacks; Junctions; Logic gates; monolithic 3-D; nanosheets; Stacking; transistor stacking; wet etching
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2024.3371946

Monolithic 3-D stacked Ge0.9Sn0.1 nanosheet and Ge0.75Si0.25 nanosheet complementary FETs with multiple P/N junction isolation by in-situ doped CVD epitaxy are experimentally demonstrated. Heterogeneous channels with common single work function metal (WFM) gate structure are fabricated as a CMOS inverter with the matched <inline-formula> <tex-math notation="LaTeX">{V}_{\text {T}} </tex-math></inline-formula> and good voltage transfer characteristics (VTCs). <inline-formula> <tex-math notation="LaTeX">{V}_{\text {T}} </tex-math></inline-formula> tuning is achieved individually by the band alignment of GeSi and GeSn for n-channel and p-channel, respectively, for the first time. The Hf0.2Zr0.8O2 gate stacks with extremely high <inline-formula> <tex-math notation="LaTeX">\boldsymbol {\kappa } </tex-math></inline-formula> of 47 are integrated to enhance the <inline-formula> <tex-math notation="LaTeX">{I}_{\text {ON}} </tex-math></inline-formula> of complementary FET (CFET) for high performance. The monolithic stacked heterogeneous CFETs without the need of wafer bonding, dielectric isolation, selective epitaxial growth, and dual WFM can simplify the process for transistor 3-D stacking.