A generalized EKV charge-based MOSFET model including oxide and interface traps. (March 2021)

• Record Type: Journal Article
• Authors: Zhang, Chun-Min; Jazaeri, Farzan; Borghello, Giulio; Mattiazzo, Serena; Baschirotto, Andrea; Enz, Christian
• Is Part Of: Solid-state electronics. Volume 177(2021)
• Publication Date: 2021-03
• Subjects: Charge-based modeling -- Charge-trapping -- Defects -- Device reliability -- EKV -- Interface traps -- Mobile charge linearization -- Oxide-trapped charges -- 28-nm bulk MOSFETs -- Radiation damage -- Total ionizing dose; Semiconductors -- Periodicals; Semiconducteurs -- Périodiques; 621.38152
• DOI: 10.1016/j.sse.2020.107951
• Languages: English
• ISSNs: 0038-1101

Abstract

Highlights: This work presents a generalized EKV charge-based MOSFET model that includes the effects of trapped charges in the oxide bulk and at the silicon/oxide interface- and can be applied for modeling effects of total ionizing dose, bias-temperature instability, and hot-carrier injection. In the presence of oxide- and interface-trapped charges, the mobile charge density at a given gate-to-bulk voltage can still be linearized but with respect to both the surface potential and the channel voltage, which enables us to derive explicit expressions for the charge-voltage relation, the current-charge relation, and crucial device parameters. The proposed charge-based analytical model, including the effect of velocity saturation, is successfully validated against a 28-nm bulk CMOS technology with pre-radiation and radiation measurements of various MOSFETs up to 1 Grad(SiO2 ) of total ionizing dose. Despite a small number of parameters, the model accurately captures the effects of radiation-induced oxide- and interface-trapped charges, resulting in an excellent fit with measurement results over a wide range of device operation from weak to strong inversion. Explicit expressions of device parameters allow for the extraction of the oxide- and interface-trapped charge densities at each radiation step, which can serve for compact modeling of total ionizing radiation effects. Abstract: This paper presents a generalized EKV charge-based MOSFET model that includes the effects of trapped charges in the oxide bulk and at the silicon/oxide interface. It is shown that in the presence of oxide- and interface-trapped charges, the mobile charge density can still be linearized but with respect to both the surface potential and the channel voltage. This enables us to derive closed-form expressions for the mobile charge density and the drain current. These simple formulations demonstrate the effects of charge trapping on MOSFET characteristics and crucial device parameters. The proposed charge-based analytical model, including the effect of velocity saturation, is successfully validated through measurements performed on devices from a 28-nm bulk CMOS technology. Ultrahigh total ionizing doses up to 1 Grad(SiO2 ) are applied to generate oxide-trapped charges and activate passivated interface traps. Despite a small number of parameters, the model is capable of accurately capturing measurement results over a wide range of device operation from weak to strong inversion. Explicit expressions of device parameters also allow for the extraction of the oxide- and interface-trapped charge densities.