Line and Point Tunneling in Scaled Si/SiGe Heterostructure TFETs

• Published in: IEEE electron device letters Vol. 35; no. 7; pp. 699 - 701
• Main Authors: Schmidt, Matthias, Schafer, Anna, Minamisawa, Renato A., Buca, Dan, Trellenkamp, Stefan, Hartmann, Jean-Michel, Qing-Tai Zhao, Mantl, Siegfried
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.07.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Compound structure devices; Electronics; Exact sciences and technology; hetero-structure; line tunneling; Logic gates; Photonic band gap; scaling; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Silicon; Silicon germanium; silicon-germanium (SiGe); strain; Transistors; Tunneling; Tunneling field-effect transistors (TFETs); Tunneling field-effect transistors (TFETs); strain; silicon-germanium (SiGe); scaling; line tunneling; hetero-structure; Voltage current curve; Circuit design; Ge-Si alloys; Tunnel effect; Short channel; Long channel; p type semiconductor; n type semiconductor; Silicon; Computer aided design; Binary alloy; Electrical characteristic; Passivation; Semiconductor alloys; Annealing; Tunnel transistors; Field effect transistor; Germanium; Heterostructures
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2014.2320273

In this letter, we systematically investigate the impact of gate length and channel orientation on the electrical performance of tunneling field-effect transistors (TFETs). We fabricate and characterize Si/SiGe heterostructure TFETs with p-doped compressively strained Si 0.5 Ge 0.5 source, intrinsic Si channel, and n-doped Si drain. We observe a linear relation of gate length, L g , and ON-current, I ON , which is the first experimental proof of line tunneling occurring in a TFET. TCAD simulations support our observations. After forming gas annealing, short-channel TFETs exhibit different I-V characteristics compared with long-channel devices due to better passivation.