Back-gate effects on DC performance and carrier transport in 22 nm FDSOI technology down to cryogenic temperatures

• Published in: Solid-state electronics Vol. 193; p. 108296
• Main Authors: Han, Hung-Chi, Jazaeri, Farzan, D’Amico, Antonio, Zhao, Zhixing, Lehmann, Steffen, Kretzschmar, Claudia, Charbon, Edoardo, Enz, Christian
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2022
• Subjects: 22 nm FDSOI; Back-gate effects; Characterization; Cryogenic CMOS; cryogenic MOSFET; Double-gate; Low temperature; Mobility; Quantum computing; Quantum transport; Characterization; Double-gate; Quantum computing; Back-gate effects; 22 nm FDSOI; cryogenic MOSFET; Mobility; Cryogenic CMOS; Quantum transport; Low temperature
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2022.108296

•Investigating carrier transport of long/short transistors of 22nm FD-SOI CMOS technology by lowering the temperature and sweeping back-gate voltage.•Intersubband scattering pronouncing at low temperatures that is less significant in short devices due to high ballisticity.•Proposing the ballistic transport as an alternative explanation to the mobility of short devices that is less-enhanced at cryogenic temperatures due to drift-diffusion-based extraction methodology.•Proposing the source-to-drain tunneling as an alternative mechanism that makes subthreshold swing saturate to 30 mV/dec due to a strong drain-to-source voltage. This paper presents an in-depth DC characterization of a 22 nm FDSOI CMOS technology down to deep cryogenic temperature, i.e., 2.95 K. The impact of the back-gate voltage (Vback) on device performance, i.e., threshold voltage (VT) and carrier transport, is investigated over a wide temperature range. Moreover, semiclassical and quantum transports of two-dimensional carrier gas are investigated. The effective mobility (μeff) extracted from short devices at cryogenic temperatures is lower than actual mobility due to the presence of ballistic transport. The discontinuous ID–VG is found in both long and extremely short transistors, which is ascribed to the intersubband transition happening during the scattering event. Oscillatory ID–VG due to resonant tunneling manifests itself in short devices at cryogenic temperatures and depends on Vback. On the other hand, the worse subthreshold swing is found for short devices in the saturation regime and at cryogenic temperatures due to source-to-drain tunneling.