Density-dependent electron transport and precise modeling of GaN high electron mobility transistors

We report on the direct measurement of two-dimensional sheet charge density dependence of electron transport in AlGaN/GaN high electron mobility transistors (HEMTs). Pulsed IV measurements established increasing electron velocities with decreasing sheet charge densities, resulting in saturation velo...

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Veröffentlicht in:Applied physics letters 2015-10, Vol.107 (15)
Hauptverfasser: Bajaj, Sanyam, Shoron, Omor F., Park, Pil Sung, Krishnamoorthy, Sriram, Akyol, Fatih, Hung, Ting-Hsiang, Reza, Shahed, Chumbes, Eduardo M., Khurgin, Jacob, Rajan, Siddharth
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Sprache:eng
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Zusammenfassung:We report on the direct measurement of two-dimensional sheet charge density dependence of electron transport in AlGaN/GaN high electron mobility transistors (HEMTs). Pulsed IV measurements established increasing electron velocities with decreasing sheet charge densities, resulting in saturation velocity of 1.9 × 107 cm/s at a low sheet charge density of 7.8 × 1011 cm−2. An optical phonon emission-based electron velocity model for GaN is also presented. It accommodates stimulated longitudinal optical (LO) phonon emission which clamps the electron velocity with strong electron-phonon interaction and long LO phonon lifetime in GaN. A comparison with the measured density-dependent saturation velocity shows that it captures the dependence rather well. Finally, the experimental result is applied in TCAD-based device simulator to predict DC and small signal characteristics of a reported GaN HEMT. Good agreement between the simulated and reported experimental results validated the measurement presented in this report and established accurate modeling of GaN HEMTs.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4933181