The Impact of Bias Conditions on Self-Heating in AlGaN/GaN HEMTs

• Published in: IEEE transactions on electron devices Vol. 60; no. 1; pp. 159 - 162
• Main Authors: Sukwon Choi, Heller, E. R., Dorsey, D., Vetury, R., Graham, S.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01-01-2013; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Aluminum gallium nitride; Aluminum gallium nitrides; Applied sciences; Bias; Channels; Devices; Electronics; Exact sciences and technology; Gallium nitride; Gallium nitride (GaN); Gallium nitrides; HEMTs; High electron mobility transistors; high electron mobility transistors (HEMTs); Logic gates; MODFETs; Phonons; Power dissipation; Raman scattering; semiconductor device reliability; Semiconductor devices; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Studies; Temperature measurement; Testing, measurement, noise and reliability; Transistors; Ternary compound; Performance evaluation; Binary compound; Semiconductor device reliability; Charge carrier density; Hot spot; Thermal behavior; Aluminium nitride; Gallium nitride (GaN); Transistor gate; Gallium nitride; III-V compound; Accelerated aging test; Temperature measurement; Heat source; High electron mobility transistor; Electric field; Field distribution; Raman scattering; Energy dissipation; Self heating; Raman spectrometry; Thermal model; high electron mobility transistors (HEMTs)
• ISSN: 0018-9383; 1557-9646
• DOI: 10.1109/TED.2012.2224115

The thermal response of AlGaN/GaN high electron mobility transistors directly correlates with the overall performance and reliability of these devices. In general, a hot spot develops near the drain end of the gate electrode during power dissipation. The device channel temperature was examined via micro-Raman spectroscopy under various bias conditions where power dissipation levels were identical. Under these bias conditions, difference in internal states (sheet carrier density and electric held distribution) within the device alters the heat generation profile across the channel. High V ds conditions lead to significantly higher channel temperature compared to that for low V ds conditions although the power dissipation is kept constant. Experimental results show ~13°C deviation between V ds = 45 V and V ds = 7 V cases when the power dissipation is 4.5 W/mm. This suggests that bias conditions may have a relatively signihcant impact on device reliability and that this effect must be considered when building thermal models of devices under operation or undergoing accelerated life testing.