Anwar Jarndal

A new small-signal modeling approach applied to GaN devices

A new small-signal modeling approach applied to GaN-based devices is presented. In this approach, a new method for extracting the parasitic elements of the GaN device is developed. This method is based on two steps, which are: 1) using cold S-parameter measurements, high-quality starting values for the extrinsic parameters that would place the extraction close to the global minimum of the objective function for the distributed equivalent circuit model are generated and 2) the optimal model parameter values are searched through optimization using the starting values already obtained. The bias-dependent intrinsic parameter extraction procedure is improved for optimal extraction. The validity of the developed modeling approach and the proposed small-signal model is verified by comparing the simulated wide-band small-signal S-parameter, over a wide bias range, with measured data of a 0.5-/spl mu/m GaN high electron-mobility transistor with a 2/spl times/50 /spl mu/m gatewidth.

An accurate small-signal model for AlGaN-GaNHEMT suitable for scalable large-signal model construction

The validity of the proposed small-signal model (SSM) and the developed extraction method in for large GaN devices is investigated. Extraction of parasitic elements is performed for different size devices to show the scaling of these elements with the gate width. The model shows a very good result for describing the parasitic distributed effect, which is considerable for large devices.

A new small signal model parameter extraction method applied to GaN devices

A new parasitic elements extraction method applied to GaN devices is presented. First, using cold S-parameter measurements, high quality starting values for the extrinsic parameters are generated that would place the extraction close to the global minimum of the objective function for the distributed equivalent circuit model. In a second step, the optimal model parameter values are searched through optimization using the starting values already obtained. The validity of the developed method and the proposed small-signal model is verified by comparing the simulated wide-band small-signal S-parameter, over a wide bias range, with measured data of a 0.5 /spl mu/m GaN HEMT with 2 /spl times/ 50 /spl mu/m gate width.

Accurate Large-Signal Modeling of AlGaN-GaN HEMT Including Trapping and Self-Heating Induced Dispersion

An accurate large-signal model for AlGaN-GaN HEMT is presented. This model is derived from a distributed small-signal model that efficiently describes the physics of the device. An improved drain current model accounts for trapping and self-heating effects is implemented. The model shows very good results for simulating the high-power operation of a 8times125mum gate width AlGaN-GaN HEMT even beyond the 1-dB gain compression point

A New Method for Identification and Minimization of Distortion Sources in GaN HEMT Devices Based on Volterra Series Analysis

This letter mainly focuses on providing theoretical justification for possible gallium-nitride (GaN) device linearity improvement, interpreting the key physical origins of third-order distortion (IMD3). Based on the bias-dependent S-parameter measurement data of field-plate (FP)-free 8times125 mum GaN high-electron mobility transistor (HEMT), IMD3 is modeled using classical Volterra series theory. Through this technique, device diagnosis is carried out for efficiently localizing the distortion behavior. Further, device linearity is shown to improve by appropriately tuning the gate-drain feedback capacitance by taking advantage of FP technology proving the analysis to be a powerful tool for developing GaN HEMT technology

A Reliable Model Parameter Extraction Method Applied to AlGaN/GaN HEMTs

In this paper, a reliable small-signal model parameter extraction method for GaN high electron mobility transistor (HEMT) on Si substrate has been developed and validated with respect to different gate width devices. The main advantage of this approach is its accuracy and dependency on only pinched-off and unbiased S-parameter measurements. The developed procedure shows reliable and physically relevant results for the investigated devices and scaled with the gate width. A very good agreement is obtained between small-and large-signal simulations and measurements of the considered GaN HEMTs.

Measurements uncertainty and modeling reliability of GaN HEMTs

In this paper, an important factors for accurate modeling of GaN HEMT is presented. Measurement uncertainty and frequency range as rules of thumb for reliable extraction of the small-signal model parameter is demonstrated. Determining the optimal pinch-off bias condition as a key point for reliable extraction of the reactive extrinsic parameters of the model is also investigated. The results of this study, which is carried out on high-power large size (in the order of 1mm gate width) devices, shows that the mentioned three points should be considered during modeling process.

A New GaN HEMT Equivalent Circuit Modeling Technique Based on X-Parameters

In this paper, a new accurate small-and large-signal equivalent-circuit-based modeling technique for gallium nitride (GaN) HEMT transistors grown on silicon substrate is presented. Despite X-parameters are developed as tools for the development of black-box modeling, they are used for equivalent-circuit-based model extraction. Unlike traditional modeling that uses the small-signal data to build with an indirect manner a nonlinear model, the proposed model is extracted from X-parameter measurements directly. However, similar to the equivalent-circuit-based models discussed in the literature, the new model is subdivided into extrinsic and intrinsic parts. The extrinsic part consists of linear elements and is related to the physical layout of the transistor. The intrinsic part can be extracted with the proposed analytical de-embedding technique. The nonlinear intrinsic elements are represented by new nonlinear lumped impedances and admittances whose extraction is carried out using a newly proposed technique. This new technique uses nonlinear network parameters, various X-parameter conversion rules, and basic analysis techniques of interconnected nonlinear networks. It is accurate and more advantageous than traditional transistor modeling techniques. The modeling procedure was applied to a 10 μm × 200 μm GaN HEMT with a gate length of 0.25 μm. A very good accordance between model simulations and measurements was obtained, validating the modeling approach.

A two stage green supplier selection and order allocation using AHP and multi-objective genetic algorithm optimization

Green supplier selection and order allocation problem involves multi-criteria decisions. In this paper, the available suppliers are ranked based on selected green criteria by decision makers in the purchasing department using analytic hierarchy process (AHP). Then, genetic algorithm (GA), that uses real-coded representation chromosomes, is used to find the optimal solution for the multi-objective integer linear programming model. The model deals with three conflicting objectives which are: total purchasing cost (TCP), total green value of purchasing (TGVP) and total rejected item due to quality (TR). The model is illustrated by a numerical example.

A simple, direct and reliable extraction method applied to GaN devices

ABSTRACT In this article, a simple, direct and reliable extraction method has been developed and applied to different sizes of Gallium Nitride (GaN) high electron mobility transistors (HEMTs). Instead of high-voltage gate-forward measurements with risk of device damage, the proposed approach uses only uncritical cold S-parameters at pinch-off (VGS < Vp, VDS = 0 V) and in the off-state (VGS = 0 V, VDS = 0 V). The extraction procedure is validated by small- and large-signal measurements. Very good agreement is obtained. Scaling of parasitic elements with the device size is confirmed.