Abstract
This paper presents two structures of wide band gap high electron mobility transistor (HEMT). One structure is made-up of a stack of AlGaN layer over GaN layer. This structure is characterized by two-dimensional (2-D) electron gas layer formed at the interface of the AlGaN and GaN layers. The 2-D electron gas plays an important role in determining the carrier-mobility \((\upmu )\) and hence drain-to-source current \((I_\mathrm{DS})\) of HEMT. The other structure introduces an AlN spacer layer between the AlGaN and GaN layers to improve these characteristics. This paper compares the output characteristics curves \((I_\mathrm{DS}-V_\mathrm{DS})\) and transconductance characteristics curves \((I_\mathrm{DS}-V_\mathrm{GS})\) obtained from simulations performed using Silvaco \(\hbox {ATLAS}^\mathrm{TM}\). The modified structure with spacer layer shows improvements in carrier-mobility and hence drain-to-source current. This paper estimates and compares the subthreshold slope (SS) of the two devices. AlGaN/AlN/GaN HEMT offers an SS of 80 mV/decade whereas AlGaN/GaN HEMT offers an SS of 95 mV/decade. Thus, an improvement in SS of about 18.75 % is achieved in AlGaN/AlN/GaN HEMT compared to AlGaN/GaN HEMT. HEMT with spacer layer also offers 10\(\times \) improvement in \(I_{DS}\) as compared to HEMT without spacer layer. The proposed HEMTs achieve \(\approx \)3.19\(\times \) improvement in breakdown voltage, \(>\)1.3\(\times \) improvement in SS compared to HEMTs previously proposed in the literature.
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References
Manel, C., Hafedh, B., Mohamed Ali, Z.: 2-D theoretical model for current-voltage characteristics. J. Mod. Phys. 3, 881–886 (2012)
Puzyrev, Y., Mukherjee, S., et al.: Gate bias dependence of defect-mediated hot carrier degradation in GaN HEMTs. IEEE Trans. Electron Device 61(5), 1316–1320 (2014)
Kikkawa, T.: GaN device for highly efficient power amplifiers. FUJITSU Sci. Tech. J. 48(1), 40–46 (2012)
Mishra, U.K., Parikh, P., Wu, Y.F.: AlGaN/GaN HEMTs: an overview of device operation and applications. Proc. IEEE 90(6), 1022–1031 (2002)
Abdel, M.A., El-Abd, A.: Theoretical study of‘the charge control in AlGaN/GaN HEMTs. In: The 23rd National Radio Science Conference (NRSC 2006), pp. 1–7 (2006)
Chung, J.W., Roberts, J.C., Piner, E.L., Palacios, T.: Effect of gate leakage in the subthreshold characteristics of AlGaN/GaN HEMTs. IEEE Electron Device Lett. 29(11), 1196–1198 (2008)
Chung, J.W., Zhao, X., Palacios, T.: Estimation of trap density in AlGaN/GaN HEMTs from subthreshold slope study. In: 65th Annual device Research Conference, pp. 111–112 (2007)
Then, H.W., et al.: IEDM Tech. Dig. 28.3.1 (2013) in AlGaN/GaN HEMT’s. J. Mod. Phys. 3, 881–886 (2012)
Binari, S.C., et al.: Trapping effects in GaN and SiC microwave FETs. Proc. IEEE 90(6), 1048–1058 (2002)
Sridharan, S., Venkatachalam, A., Yoder, P.D.: Electrothermal analysis of AlGaN/GaN high electron mobility transistors. J. Comput. Electron. 7(3), 236–239 (2008)
Torres-Rios, E., Saavedra, C.: A new compact nonlinear model improvement methodology for GaN-HEMT. In: 2014 IEEE 5th Latin American Symposium on Circuits and Systems (LASCAS), pp. 1–4. IEEE, 2014
Cabral, P.M., Pedro, J.C., Carvalho, N.B.: Nonlinear device model of microwave power GaN HEMTs for high power-amplifier design. IEEE Trans. Microwav. Theory Tech. 52(11), 2585–2592 (2004)
Silvaco, Version 5.15.32.R.: http://www.silvaco.com (2009)
Mohiuddin, M. et al.: 2-D Physical Modelling of 6-doped GaAs/AlGaAs HEMT, In: ASDAM 2008, The Seventh International Conference on Advanced Semiconductor Devices and Microsystems, (2008), Smolenice Castle, Slovakia, pp. 207–210 (2008)
Shen, L., et al.: AlGaN/AlN/GaN high power microwave HEMT. IEEE Electron Device 22(10), 457–459 (2001)
Hao, Y., et al.: High performance gate recessed AlGaN/AlN/GaN MOS HEMT with 73 power-added efficiency. IEEE Electron Device 32(5), 626–628 (2011)
Mohanbabu, A., et al.: Modeling of sheet carrier density and microwave frequency characteristics in Spacer based AlGaN/AlN/GaN HEMT devices. Solid-State Electron. 91, 44–52 (2014)
Asgari, A., Kalafi, M., Faraone, L.: A quasi-two-dimensional charge transport model of AlGaN/GaN high electron mobility transistors (HEMTs). Physica E 28(4), 491–499 (2005)
Ohi, K., Hashizume, T.: Drain current stability and controllability of threshold voltage and subthreshold current in a multi-mesa channel alGaN/GaN HEMT. Jpn. J. Appl. Phys. 48, 081002 (2009)
Tang, Y., et al.: High-performance monolithically integrated E/D mode InAlN/AlN/GaN HEMTs for mixed signal applications, In: IEEE International Electron Devices Meeting (IEDM), pp. 30.4.1–30.4.4 (2010)
Smit, G.D., Scholten, A.J., Pijper, R.M., Tiemeijer, L.F., van der Toorn, R., Klaassen, D.B.: RF-Noise modeling in advanced CMOS technologies. IEEE Trans. Electron Device 61(2), 245–254 (2014)
Shen, L., Heikman, S., Moran, B., Coffie, R., Zhang, N.-Q., Buttari, D., Smorchkova, I.P., Keller, S., DenBaars, S.P., Mishra, U.K.: AlGaN/AlN/GaN high-power microwave HEMT. IEEE Electron Device Lett. 22(10), 457–459 (2001)
Boudrissa, M., Delos, E., Gaquiere, C., Rousseau, M., Cordier, Y., Didier, T., Jaeger, J.C.: Enhancement-mode Al 0.66 In 0.34 As/Ga 0.67 In 0.33 As metamorphic HEMT, modeling and measurements. IEEE Trans. Electron Device 48(6), 1037–1044 (2001)
Hsu, L., Walukiewicz, W.: Effect of polarization fields on transport properties in AlGaA/GaN heterostructures. J. Appl. Phys. 89, 1783–1789 (2001)
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Prasad, S., Dwivedi, A.K. & Islam, A. Characterization of AlGaN/GaN and AlGaN/AlN/GaN HEMTs in terms of mobility and subthreshold slope. J Comput Electron 15, 172–180 (2016). https://doi.org/10.1007/s10825-015-0751-8
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DOI: https://doi.org/10.1007/s10825-015-0751-8