A novel method for extracting threshold voltage and substrate effect parameters of MOSFETs with constant current bias at all levels of inversion is presented. This generalized constant-current (GCC) method exploits the charge-based model of MOSFETs to extract threshold voltage and other substrate-effect-related parameters. The method is applicable over a wide range of current throughout weak and moderate inversion, and to some extent in strong inversion. This method is particularly useful when applied for MOSFETs presenting edge conduction effect (subthreshold hump) in CMOS processes using shallow trench isolation (STI).
10 May 2018 in IEEE Transactions on Electron Devices
We present a unified charge-based model for double-gate and cylindrical architectures of junction field-effect transistors (JFETs). The central concept is to consider the JFET as a junctionless FET (JLFET) with an infinitely thin insulating layer, leading to analytical expressions between charge densities, current, and voltages without any fitting parameters. Assessment of the model with numerical technology computer-aided design simulations confirms that holding the JFET as a special case of the JLFET is justified in all the regions of operation, i.e., from deep depletion to flat-band and from linear to saturation.
4 June 2018 in IEEE Transactions on Electron Devices
The double-gate (DG) junction field-effect transistor (JFET) is a classical electron device, with a simple structure that presents many advantages in terms of not only device fabrication but also its operation. The device has been largely used in low-noise applications, but also more recently, in power electronics. Physics-based, compact models for JFETs, contrary to MOSFETs, are, however, scarce. In this paper, an analytical, charge-based model is established for the mobile charges, drain current, and transconductances of symmetric DG JFETs, covering all regions of device operation. The model is unified and continuous from subthreshold to linear and saturation operation and is valid over a large temperature range. This charge-based model constitutes the basis of a full compact model of the DG JFET.
6 June 2018 in IEEE Transactions on Electron Devices
A compact model for the dynamic operation of double-gate junction field-effect transistors is established in this paper. Analytical model expressions are developed for the total node charges and transcapacitances valid from subthreshold to above threshold and from linear to saturation operation. The model is shown to conserve symmetry among source and drain, and circumvents problems at zero drain-to-source bias.
1 October 2019 in IEEE Journal of the Electron Devices Society
The double-gate (DG) junction field-effect transistor (JFET) is a classical electron device, with a simple structure that presents many advantages in terms of device fabrication but also its principle of operation. The device has been largely used in low-noise applications, but also more recently, in power electronics. Furthermore, co-integration of JFET with CMOS technology is attractive. Physics-based compact models for JFETs are however scarce. In this paper, an analytical, charge-based model is established for the mobile charges, drain current, transconductances and transcapacitances of symmetric DG JFETs, covering all regions of device operation, continuously from subthreshold to linear and saturation operation. This charge-based JFET model (called CJM) constitutes the basis of a full compact model of the DG JFET for analog, RF, and digital circuit simulation.
This work presents an analysis of high frequency noise and linearity performance of a 90 nm CMOS process. Measurements are performed for a wide range of nominal gate lengths and bias points at high frequency. Modeling is based on the EKV3 compact model in Spectre RF circuit simulator from Cadence. The model shows correct scalability for noise and linearity accounting for short channel effects (SCEs), such as velocity saturation (VS) and channel length modulation (CLM). Results are presented versus a common measure of channel inversion level, named inversion coefficient. Optimum performance is shown to gradually shift from higher to lower levels of moderate inversion, when scaling from 240 nm to 100 nm. The same trend is observed from investigating the transconductance frequency product (TFP) of a common-source (CS) LNA for technology nodes ranging from 180 nm to 22 nm.