Comparative Cryogenic Investigation of FD-SOI Devices with Doped Epitaxial and Metallic Source/Drain

• Published in: ECS journal of solid state science and technology 2024-06, Vol.13 (6), p.65001
• Main Authors: Su, Xueyin, Xu, Binbin, Tang, Bo, Xu, Jing, Liu, Jinbiao, Cui, Yan, Yang, Meiyin, Chen, Bohan, Tong, Keyou, Zhao, Guanyuan, Li, Binhong, Wang, Xiaolei, Ye, Tianchun, Luo, Jun
• Format: Article
• Language: English
• Subjects: cryogenic; electron devices; epitaxial; FD-SOI; microelectronics - semiconductor processing; schottky barrier; source/drain
• ISSN: 2162-8769; 2162-8777
• DOI: 10.1149/2162-8777/ad4de0

Defects induced by the source/drain process have a significant impact on the scattering mechanism of PMOS at cryogenic temperatures. Here, the cryogenic characteristics of FD-SOI devices with heavily doped epitaxial source/drain (Epi FD-SOI devices) and metallic Schottky barrier source/drain (SB FD-SOI devices) were investigated from 300 K down to 6 K. The doping profile along the channel was analyzed by TCAD simulation analysis. Experimental comparison of transistor performance at cryogenic temperatures was carried out for these devices with gate lengths ( L G ) of 100 nm and 40 nm. The I - V characteristics of the FD-SOI devices were measured with a liquid helium cooling environment. The cryogenic effect of the two types of devices on Key parameters including transconductance ( G m ), field effect mobility ( μ FE ), threshold voltage ( V th ) and subthreshold slope ( SS ) were systematically analyzed. The doping distribution of the heavily doped epitaxial SiGe source/drain structure were subjected to more Coulomb scattering at cryogenic temperatures, whereas the doping distribution of the Schottky-barrier source/drain structure dictates that the device is mainly subjected to phonon scattering at cryogenic temperatures.