ABSTRACT A threshold-voltage-based 2-D theoretical model for the Current–Voltage characteristics of the AlGaN/GaN high electron mobility transistors (HEMT’s) is developed. The present work proposes an improved charge-control model by employing the Robin boundary condition when introduced the solution of the 2-D Poisson’s equation in the density of charge depleted in the AlGaN layer. The dependence of 2-DEG sheet carrier concentration on the aluminum composition and AlGaN layer thickness has been investigated in detail. Current–voltage characteristics developed from the 2-DEG model in order to take into account the impact of gate lengths. The relation between the kink effect and existing deep centers has also been confirmed by using an electrical approach, which can allow to adjust some of electron transport parameters in order to optimize the output current.
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M. Charfeddine, H. Belmabrouk, M. Zaidi and H. Maaref, "2-D Theoretical Model for Current–Voltage Characteristics in AlGaN/GaN HEMT’s," Journal of Modern Physics, Vol. 3 No. 8, 2012, pp. 881-886. doi: 10.4236/jmp.2012.38115.
 T. Tanaka, K. Takano, T. Mishima, Y. Kohji, Y. Otoki and T. Meguro, “GaN Epitaxial Wafers for High Breakdown Voltage RF Transistor Applications,” Hitachi Cable Review, No. 24, 2005, pp. 11-14.
 P. Gangwani, S. Pandey, S. Haldar, M. Gupta and R.S. Gupta, “Polarization Dependent Analysis of AlGaN/GaN HEMT for High Power Applications,” Solid State Electronics, Vol. 51, No. 1, 2007, pp. 130-135. doi:10.1016/j.sse.2006.11.002
 X. L. Wang, T. S. Shen, H. L. Xiao, C. M. Wang, G. X. Hu, W. J. Luo, J. Tang, L. C. Guo and J. M. Li, “High-Performences 2 mm Gate width GaN HEMTs on 6H-SiC with Output Power of 22.4 W at 8 GHz,” Solid-State Electron, Vol. 58, No. 6, 2008, pp. 926-929. doi:10.1016/j.sse.2007.12.014
 D. Ducatteau, A. Minko, V. Ho?l, E. Morvan, E. Delos, B. Grimbert, H. Lahreche, P. Bove, C.Gaquière, J. C. De Jaeger and S. Delage, “Output Power Density of 5.1/mm at 18 GHz with an AlGaN/GaN HEMT on Si Substrate,” IEEE Electron Device Letters, Vol. 27, No. 1, 2006, pp. 7-9. doi:10.1109/LED.2005.860385
 I. Saidi, Y. Cordier, M. Chmielowska, H. Mejri and H. Maaref, “Thermal Effects in AlGaN/GaN/Si High Elec- tron Mobility Transistors,” Solid-State Electronics, Vol. 61, No. 1, 2011, pp. 1-6. doi:10.1016/j.sse.2011.02.008
 M. K. Chattopadhyay and S. Tokekar, “Thermal Model for dc Characteristics of Algan/Gan Hemts Including Self-Heating Effect and Non-Linear Polarization,” Micro- electronics Journal, Vol. 39, No. 10, 2008, pp. 1181-1188. doi:10.1016/j.mejo.2008.01.043
 R. K. Tyagi, A. Ahlawat, M. Pandey and S. Pandey, “An Analytical Two-Dimensional Model for AlGaN/GaN HEMT with Polarization Effects for High Power Applications,” Microelectronics Journal, Vol. 38, No. 8-9, 2007, pp. 877-883. doi:10.1016/j.mejo.2007.07.003
 E. J. Miller, “Trap Characterization by Gate-Drain Con- ductance and Capacitance Dispersion Studies of an AlGaN/GaN Heterostructure Field Effect Transistor,” Journal of Applied Physics, Vol. 87, No. 11, 2000, pp. 8070- 8073. doi:10.1063/1.373499
 S. Saadaoui, M. M. Ben Salem, M. Gassoumi, H. Maaref and C. Gaquière, “Electrical Characterization of (Ni/Au)/ Al0.25Ga0.75N/GaN/SiC Schottky Barrier Diode,” Journal of Applied Physics, Vol. 110, No. 1, 2011, pp. 1-6. doi:10.1063/1.3600229
 M. Gassoumi, J. M. Bluet, G. Guillot, C. Gaquière and H. Maaref, “Characterization of Deep Levels in High Elec- tron Mobility Transistor by Conductance Deep Level Transient Spectroscopy,” Materials Science and Engi- neering C, Vol. 26, 2006, pp. 787-790.
 I. Saidi, M. Gassoumi, H. Maaref, H. Mejri and C. Gaquière, “Self-Heating and Trapping Effects in AlGaN/ GaN Heterojunction Field-Effect Transistors,” Journal of Applied Physics, Vol. 106, 2009, pp. 1-7.
 Rashmi, A. Kranti, S. Haldar, M. Gupta and R. S. Gupta, “An Accurate Charge Control Model for Spontaneous and Piezoelectric Polarization Dependent Two-Dimensional Electron Gas Sheet Charge Density of Lattice-Mismatched AlGaN/GaN HEMTs,” Solid-State Electronics, Vol. 46, No. 5, 2002, pp. 621-630. doi:10.1016/S0038-1101(01)00332-X
 X. Cheng, M. Li and Y. Wang, “An Analytical Model for Current-Voltage Characteristics of AlGaN/GaN HEMTs in Presence of Self-Heating Effect,” Solid-State Electronics, Vol. 54, No. 1, 2010, pp. 42-47.
 E. W. Faraclas and A. F. M. Anwar, “AlGaN/GaN HEMTs: Experiment and Simulation of DC Characteristics,” Solid-State Electronics, Vol. 50, No. 6, 2006, pp. 1051-1056. doi:10.1016/j.sse.2006.04.014
 M. Gassoumi, M. M. Ben Salem, S. Saadaoui, B. Grim bert, J. Fontaine, C. gaquiere and H. Maaref, “ The Ef- fects of Gate Lengeth Variation and Trapping Effects on Transient Response of AlGaN/GaN HEMT’s on SiC Substrates,” Microelectronic Engineering, Vol. 88, No. 4, 2011, pp. 370-372. doi:10.1016/j.mee.2010.09.027
 J. Haruyama, H. Negishi, Y. Nishimura and Y. Nashi- moto, “Substrate Related Kink Effects with a Strong Light-Sensitivity in AlGaAs/InGaAs PHEMTs,” IEEE Transactions Electron Devices, Vol. 44, No. 1, 1997, pp. 25-33. doi:10.1109/16.554787
 B. Brar and H. Kroemer, “In?uence of Impact Ionization on the Drain Conductance in InAs-AlSb Quantum Well Heterostructure ?eld-Effect Transistors,” IEEE Electron Device Letters, Vol. 16, No. 12, 1995, pp. 548-550. doi:10.1109/55.475583
 B. Brar, K. Boutros, R. E. DeWames, V. Tilak, R. Shealy and L. Eastman, “Impact Ionization in High Performance AlGaN/GaN HEMTs,” IEEE Lester Eastman Conference on High Performance Devices, 6-8 August 2002, pp. 487-491. doi:10.1109/LECHPD.2002.1146791
 H. F. Sun and C. R. Bolognesi, “Anomalous Behavior of Algan/Gan Heterostructure Field-Effect Transistors at Cryogenic Temperatures: From Current Collapse to Current Enhancement with Cooling,” Applied Physics Letters, Vol. 90, No. 12, 2007, Article ID: 123505. doi:10.1063/1.2715032
 M. Gassoumi, J. M. Bluet, G. Guillot, C. Gaquière and H. Maaref, “ Characterization of Deep Levels in High Electron Mobility Transistor by Conductance Deep Level Transient Spectroscopy,” Materials Science and Engineering C, Vol. 28, No. 5-6, 2008, pp. 787-790. doi:10.1016/j.msec.2007.10.068
 M. M. Ben Salem, S. Bouzgarrou, N. Sghaier, A. Kal- boussi and A. Soui?, “Correlation between Static Cha- racteristics and Deep Levels in InAlAs/InGaAs/InP HEMT’S,” Materials Science and Engineering B, 2006, Vol. 127, No. 1, pp. 34-40. doi:10.1016/j.mseb.2005.09.047
 G. Meneghesso, B. Cogliati, G. Donzelli, D. Sala and E. Zanoni, “Development of Kink in the Output I-V Characteristics OF Pseudomorphic HEMTs after Hot-Electron Accelerated Aging,” Microelectronics Reliability, Vol. 37, No. 10-11, 1997, pp. 1679-1682. doi:10.1016/S0026-2714(97)00138-8