Search

This paper presents the temperature dependence of small signal performance of GaN‐on‐diamond high electron mobility transistors (HEMTs) at an ambient temperature range from 0°C to 125°C. The temperature influence on the parasitic resistances together with the intrinsic parameters is investigated, and the temperature coefficients of these parameters are extracted from measured data. For comparison, a GaN‐on‐SiC device is also investigated. These results are important for the development and application of the GaN‐on‐diamond HEMT technology. [ABSTRACT FROM AUTHOR]

An accurate analytical electrothermal drain current (Ids) model for AlGaN/GaN HEMTs is presented in this letter. The model is implemented into our recently proposed quasi‐physical zone division (QPZD) model for demonstration purpose. Compared with the original QPZD model, its electrothermal characteristics are enhanced by involving more fundamental temperature dependent elements. In addition, these elements are derived analytically based on physical mechanisms instead of former pure empirical fitting method. Thus, the extracted parameter values are more close to intrinsic values. An in house 0.15‐μm GaN HEMT is used for validation. Compared with the measured data at a wide ambient temperature range (245‐390 K), this electrothermal model demonstrates good accuracy to predict the DC characteristics and RF performances of GaN HEMTs. [ABSTRACT FROM AUTHOR]

In this paper, a reliable and efficient parameter extraction method for GaN high electron mobility transistor (HEMT) small‐signal models has been proposed. By utilizing parameter scanning method, the initial values of the extrinsic elements are first extracted from the cold pinch‐off and cold unbiased measurement conditions, respectively. An iterative optimization algorithm is employed then to optimize the extrinsic elements. This scanning and iteration combined algorithm based on a direct extraction method of extrinsic elements can reduce the impact of the approximation error, which makes the determined values of the small‐signal parameters more reliable. The extraction flow has been realized in a Matlab program for efficiency. A 16‐element small‐signal equivalent circuit model (SSECM) for GaN HEMTs has been employed, and the new parameter extraction method has been validated by comparing the simulated small‐signal S‐parameters with the measured data from 0.1 GHz to 40 GHz for two different device dimensions. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, a scalable and multibias parameter extraction method for gallium nitride high electron mobility transistor small‐signal model has been proposed. The main advantage of this method is that the temperature‐dependent access resistances and nonlinear thermal resistance have been taken into account, which makes the extracted access resistances and intrinsic elements more physical and reliable at different bias conditions for various device dimensions. The new modeling method has been validated by comparing the simulated small‐signal S‐parameters with the measured data over a wide range of frequency. [ABSTRACT FROM AUTHOR]

The dynamic characteristics and high-frequency noise performance of junctionless (JL) metal-oxide-semiconductor field-effect transistors (MOSFETs) are investigated using a full-band Monte Carlo simulator. A detailed comparison with conventional inversion mode (IM) MOSFETs is presented. The results of the radio frequency performance indicate that, compared with the traditional IM MOSFET, the JL transistor exhibits lower drain current (Ids), transconductance (gm), and cut-off frequency (ft) because of its lower electron velocity in the high doping channel. However, owing to a reduced output conductance (gds) and a larger Cgs/Cgd ratio (Cgs is the gate-to-source capacitance; Cgd is the gate-to-drain capacitance), the JL MOSFET presents an improvement in the intrinsic voltage gain (Avo) and maximum frequency of oscillation (fmax) in comparison with the IM transistor, which makes it be a viable option for the high-voltage and power gain analog/radio frequency applications. The results of the noise characteristics show that the JL MOSFET exhibits higher minimum noise figure (NFmin) and equivalent noise resistance (Rn), indicating an inferior noise performance. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, a full-band Monte Carlo simulator is employed to study the dynamic characteristics and high-frequency noise performances of a double-gate (DG) metal-oxide-semiconductor field-effect transistor (MOSFET) with 30 nm gate length. Admittance parameters (Y parameters) are calculated to characterize the dynamic response of the device. The noise behaviors of the simulated structure are studied on the basis of the spectral densities of the instantaneous current fluctuations at the drain and gate terminals, together with their cross-correlation. Then the normalized noise parameters ( P, R, and C), minimum noise figure ( NFmin), and so on are employed to evaluate the noise performances. To show the outstanding radio-frequency performances of the DG MOSFET, a single-gate silicon-on-insulator MOSFET with the same gate length is also studied for comparison. The results show that the DG structure provides better dynamic characteristics and superior high-frequency noise performances, owing to its inherent short-channel effect immunity, better gate control ability, and lower channel noise. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]