On the Operation Mechanism and Device Modeling of AlGaN/GaN High Electron Mobility Transistors (HEMTs)

In this work, the physical based device model of AlGaN/GaN high electron mobility transistors (HEMTs) has been established and the corresponding device operation behavior has been investigated also by using Sentaurus TCAD from Synopsys. Advanced AlGaN/GaN hetero-structures with GaN cap layer and AlN spacer have been considered and the GaN cap layer and AlN spacer are found taking important roles on the gate leakage blocking and off-state breakdown voltage enhancement.

Authors:

• Li Yuan
• Weizhu Wang
• Kean Boon Lee
• Haifeng Sun
• Susai Lawrence Selvaraj
• Shane Todd
• Guo-Qiang Lo

Keywords:

• AlGaN/GaN
• HEMT
• Physical mechanism
• TCAD simulation

References:

[1] S. Khandelwal, et al., "A Physics-Based Analytical Model for 2DEG
Charge Density in AlGaN/GaN HEMT Devices," IEEE Trans. Electron
Devices, vol. 58, pp. 3622-3625, Oct. 2011.
[2] N. Ikeda, et al,. "GaN Power Transistors on Si Substrates for Switching
Applications," Proceedings of the IEEE, vol. 98, pp. 1151-1161, Jul.
2010.
[3] J. W. Chung, et al., "AlGaN/GaN HEMT With 300-GHz fmax,"
Electron Device Lett., vol. 31, pp. 195-197, Mar. 2010.
[4] A. Armstrong, et al., "Impact of Growth Pressure on Defects in GaN
Grown - by Metalorganic Chemical Vapor Deposition," Compound
Semiconductors: Post-Conference Proceedings, 2003 International
Symposium on, pp. 42-48, 2003.
[5] Y. C. Choi, et al., "The Effect of an Fe-doped GaN Buffer on OFF-State
Breakdown Characteristics in AlGaN/GaN HEMTs on Si Substrate,"
IEEE Trans. Electron Devices, vol. 53, pp. 2926-2931, Dec. 2006.
[6] A. Rizzi, et al., "Surface and interface electronic properties of
AlGaN(0001) epitaxial layers," Appl. Phys. A, vol.87, pp. 505-509, Mar.
2007.
[7] B. Jogai, "Influence of surface states on the two-dimensional electron
gas in AlGaN/GaN heterojunction field-effect transistors," J. Appl.
Phys., vol. 93, pp. 1631-1634, Feb. 2003.
[8] X. Wang, et al., "MOCVD-grown high-mobility Al0.3Ga0.7N/AlN/GaN
HEMT structure on sapphire substrate," Journal of Crystal Growth, vol.
298, pp. 791-793, 2007.
[9] R. Vetury, "The Impact of Surface States on the DC and RF
Characteristics of AlGaN/GaN HFETs," IEEE Trans. Electron Devices,
vol. 48, pp. 560-566, Mar. 2001.
[10] S. Kasai, et al., "Gate Control, Surface Leakage Currents, and Peripheral
Charging in AlGaN/GaN Heterostructure Field Effect Transistors
Having Nanometer-Scale Schottky Gates," Journal of Electronic
Materials, vol. 35, pp. 568-575, Nov. 2006.