An accurate parasitic parameters extraction method based on FW‐EM for AlGaN/GaN HEMT up to 110 GHz

Abstract

In this paper, an accurate parasitic parameters extraction method based on full wave electromagnetic for 0.1 μm GaN high electron mobility transistors (HEMTs) smallsignal equivalent circuit up to 110 GHz is presented. To describe the distribution effects of HEMTs electrodes at extremely high frequency, a 2-stage distributed transmission line equivalent circuit model is also presented. To minimize the distribution effects, a shorter gate-width device, called partial transistor model, is used to extract the second stage (N = 2) parasitic capacitance before extracting the first stage (N = 1) parameters. An AlGaN/GaN HEMT with gate length of 0.1 μm is used for validation, and the experimental results show that good agreement has been achieved between measured and simulated scattering (S) parameters up to 110 GHz. KEYWORDSAlGaN/GaN HEMTs, high frequency distribution effects, parasitic parameter model | INTRODUCTIONGaN-based high electron mobility transistors (HEMTs) are one of the most attractive solid device for high-power and high-frequency microwave devices. 1 Accurate models 2-4 can promote the efficiency of circuit design and is essential to circuit designer. With the increasing operation frequency of GaN HEMT, characterization of GaN HEMTs up to W-band is highly attracted recently. [5][6][7] At extremely high frequency, much more parasitic parameters for transistor need to be considered to account for high-frequency effects. However, the complicated parasitic parameters network will dramatically increase the difficulty of parameters extraction. Most of the papers have to use optimization method, which have challenges like multivalues problem, nonphysical results, and difficult to separate the parasitic capacitance and intrinsic capacitance. 8 It is need the guessed starting values of the parasitic parameters and a family of scaling devices be available for measurement to get the optimal values for device by Sergio. 9 Zlatica 10 used artificial neural networks for constructing a temperature-dependent model representing the small-signal scattering (S-) parameters of a GaN HEMT over a wide bias range and a board frequency range, while this method need tremendous measured data and high computer configuration. In Jarndal and Kompa, 11 a new parasitic elements extraction method based on cold pinch-off conditions was developed. This method uses only a cold-parameter measurement for accurate determination of the parasitic elements. The main advantage of this method is that it gives reliable values for the parasitic elements of the device without need for additional measurements or separate test pattern. But it needs hard task, when there are much more parasitic parameters up 110 GHz. Giovanni 12 used a new and simple T-network composed by lumped elements for representing the investigated GaN HEMT under a forward "cold" condition, which takes into account the capacitive effects of S11 and S22. All extrinsic parasitic elements are evaluated under "cold-FET" conditions without forward biasing the gate terminal. 13...

Temperature‐dependent small signal performance of GaN‐on‐diamond HEMTs

“…More details can be found in our previously published paper. [20][21][22] 3 | RESULTS AND DISCUSSION The GaN-on-diamond HEMT device with gate number of 4 and each gate finger width of 125 μm is used to extract the temperature-dependent small signal parameters. A 0.25-μm GaN HEMT on a 100-μm SiC substrate with gate number of 4 and each gate finger width of 125 μm is also investigated for comparison.…”

An Improved Large Signal Model for 0.1 μm AlGaN/GaN High Electron Mobility Transistors (HEMTs) Process and Its Applications in Practical Monolithic Microwave Integrated Circuit (MMIC) Design in W band

“…With the frequency up to W band, the RF dispersion will become more and more obvious due to the parasitic effects inside devices. A wide band small signal model [ 14 ], which has been proved to be able to cover the frequency band from 0.2–110 GHz, is employed in this work. The topology of the large signal model is shown in Figure 5 .…”

“…Firstly, the parasitic effect will become obvious with the increasing of frequency and make the parameter extraction more difficult [ 12 , 13 ]. This problem can be solved by FW-EM (Full-wave electromagnetic) simulation [ 14 ]. Secondly, along with the reduction of feature size, the short channel effect becomes obvious.…”

A reliable and efficient small‐signal parameter extraction method for GaN HEMTs

“…Numerous research works on SSECM of GaN HEMTs have been done in the past decade. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Chigeava et al 10 established a GaN HEMT 14-element SSECM by measuring "cold field-effect transistor (FET)" S-parameters (V ds = 0 V) to extract extrinsic parameters directly under a large gate voltage. Jarndal et al 11 proposed a GaN HEMT 22-element SSECM, in which a search algorithm was used to optimize the parameters.…”