Characterization and Modeling of 28-nm Bulk CMOS Technology Down to 4.2 K

• Published in: IEEE journal of the Electron Devices Society Vol. 6; pp. 1007 - 1018
• Main Authors: Beckers, Arnout, Jazaeri, Farzan, Enz, Christian
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.01.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: 28 nm bulk CMOS; 4.2 K; CMOS; CMOS technology; cryo-CMOS; cryoelectronics; cryogenic; Cryogenic engineering; Cryogenic temperature; Cryogenics; Degradation; Depletion; Field effect transistors; freeze-out; Integrated circuit modeling; interface charge traps; Modelling; MOS devices; MOS transistor modeling; Semiconductor device modeling; Semiconductor devices; slope factor; subthreshold swing; Temperature; Temperature dependence; Thickness
• ISSN: 2168-6734; 2168-6734
• DOI: 10.1109/JEDS.2018.2817458

This paper presents an experimental investigation, compact modeling, and low-temperature physics-based modeling of a commercial 28-nm bulk CMOS technology operating at cryogenic temperatures. The physical and technological parameters are extracted at 300, 77, and 4.2 K from dc measurements made on various geometries. The simplified-EKV compact model is used to accurately capture the dc characteristics of this technology down to 4.2 K and to demonstrate the impact of cryogenic temperatures on the essential analog figures-of-merit. A new body-partitioning methodology is then introduced to obtain a set of analytical expressions for the electrostatic profile and the freeze-out layer thickness in field-effect transistors operating from deep-depletion to inversion. The proposed physics-based model relies on the drift-diffusion transport mechanism to obtain the drain current and subthreshold swing, and is validated with the experimental results. This model explains the degradation in subthreshold swing at deep-cryogenic temperatures by the temperature-dependent occupation of interface charge traps. This leads to a degradation of the theoretical limit of the subthreshold swing at deep-cryogenic temperatures.