Journal of Ovonic Research Vol. 13, No. 4, July - August 2017, p. 211 - 217 DC AND RF CHARACTERISTIC OF HIGH-ELECTRON-MOBILITY TRANSISTOR (HEMT) ON AlGaN/GaN/Si FOR POWER APPLICATIONS MOUJAHED GASSOUMI a , A. HELALI a , MALEK GASSOUMI a,b* , C. GAQUIÈRE c , H. MAAREF a a Laboratory of Micro-Optoelectronics and Nanostructures (LMON), University of Monastir, 5019 Monastir, Tunisia b College of Science, Department of Physics, Qassim University, Buraidah 51452, Saudi Arabia c Institute of Electronics of Microelectronics and Nanotechnology IEMN, University of Science and Technology of Lille, Poincare Avenue, 59652 Villeneuve d'Ascq Cedex, France AlGaN/GaN/Si HEMTs grown by molecular beam epitaxy are studied with several means of characterization, the most used are direct-current and radio-frequency measurements, to see power and microwave performance of components. As has been found, the maximum of drain current achieves 0,4 A and 3,54 10 21 cm -3 of 2DEG carrier concentration. Device simulation was also carried on in ATLAS to probe into the operation mechanism of GaN HEMTs and demonstrate those result. As we used this last simulation tool to extract the Radio-frequency parameter; cut-off frequency (F t ), maximum oscillation frequency (F max ), variation maximum stable gain (G ms ) and maximum available gain (G ma ), consequently we will know the microwave power performance and area component application. (Received May 26, 2017; Accepted August 4, 2017) Keywords: AlGaN/GaN HEMT, I-V characteristics, RF, TCAD modeling, Power. 1. Introduction AlGaN/GaN high electron mobility transistors is a promising device for high-frequency and high-power applications [1, 2]. Gallium nitride is a great candidate for these applications because of its wide band gaps, strong spontaneous and piezoelectric polarization fields, large breakdown bias voltages and an efficient carrier transport [3]. A two-dimensional electron gas may occur at the AlGaN/GaN heterointerface with a relatively high density, following this last feature. In addition, the high concentration of carrier sheet and the strong confinement of the two-dimensional electron gas (2DEG) at the AlGaN/GaN HEMT heterointerface are appropriate for high speed applications [4]. A considerable improvement in the drain current and RF characteristics is also observed in the AlGaN/GaN HEMT [5]. In the present work reports on a study of AlGaN/GaN/Si HEMTs, we have also investigated the simulation of variation of 2DEG layer, current-voltage and the radio- frequency characteristics at output. An attempt to correlate all of the results. 2. Device structure The AlGaN/GaN HEMTs under investigation are grown on silicon (111) substrate by using molecular beam epitaxy (MBE) (present some high purity). The sample structure is shown in Fig.1. The active layers consist in a 500 nm thick of undoped AlN/AlGaN buffer, a 1.8 μm undoped GaN channel, a 23 nm thick of undoped Al0.26Ga0.74N barrier and a 1 nm n+-GaN cap * Corresponding author: email: gassoumimalek@yahoo.fr