Novel thermal management of power electronic devices: high power high frequency planar gunn diodes

Thermal management of next generation of semiconductor devices is becoming more challenging, as the device power increases and device dimensions decrease. The work is addressing novel thermal measurement and management for planar heterostructure Gunn diodes, which will be of strategic importance for UK technology and industry

A Temperature Analysis of High-power AlGaN/GaN HEMTs

Galliumnitride has become a strategic superior material for space, defense and civil applications, primarily for power amplification at RF and mm-wave frequencies. For AlGaN/GaN high electron mobility transistors (HEMT), an outstanding performance combined together with low cost and high flexibility can be obtained using a System-in-a-Package (SIP) approach. Since thermal management is extremely important for these high power applications, a hybrid integration of the HEMT onto an AlN carrier substrate is proposed. In this study we investigate the temperature performance for AlGaN/GaN HEMTs integrated onto AlN using flip-chip mounting. Therefore, we use thermal simulations in combination with experimental results using micro-Raman spectroscopy and electrical dc-analysis.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

Micro-cooler Enhancements by Barrier Interface Analysis

Peer reviewedPublisher PD

Fabrication of integrated planar gunn diode and micro-cooler on GaAs substrate

We demonstrate fabrication of an integrated micro cooler with the planar Gunn diode and characterise its performance. First experimental results have shown a small cooling at the surface of the micro cooler. This is first demonstration of an integrated micro-cooler with a planar Gunn diode

Planar gunn diode characterisation and resonators elements to realise oscillator circuits

The paper describes the planar Gunn diode, which is well suited to providing milli-metric and tera hertz sources using microwave monolithic integrated circuit (MMIC) technologies. Different planar Gunn electrode geometries are described along with DC, RF and thermal characterisation. To realize the planar high frequency sources there is requirement for high frequency planar resonators, the paper will describe both the radial and new diamond shaped geometries

Hot-Electron Electroluminescence under RF Operation in GaN-HEMTs::A Comparison Among Operational Classes

Electroluminescence microscopy and spectroscopy are used to compare the average hot-electron concentration and temperature under radio frequency (RF) operation class A, class B, and class F modes. From the results obtained, class A results, on average, in the highest hot-electron concentration, while class F is the mode with the lowest concentration due to its “L”-shaped load line. The electron temperature extracted from the electroluminescence spectra is reduced with increasing RF power, reflecting the dominance of electroluminescence from the portion of the load line in the semi-on region. The electroluminescence method is not able to give substantial information on the portion of the load line with high field and low current density which will be responsible for the potentially damaging hottest electrons present in the channel

InN thin film lattice dynamics by grazing incidence inelastic x-ray scattering

Achieving comprehensive information on thin film lattice dynamics so far has eluded well established spectroscopic techniques. We demonstrate here the novel application of grazing incidence inelastic x-ray scattering combined with ab initio calculations to determine the complete elastic stiffness tensor, the acoustic and low-energy optic phonon dispersion relations of thin wurtzite indium nitride films. Indium nitride is an especially relevant example, due to the technological interest for optoelectronic and solar cell applications in combination with other group III nitrides.J. S. acknowledges financial support from the Spanish Ministry of Science and Innovation by CICYT Grants No. MAT2010-2-129-C02-01 and No. ENE2008-04373, and by Generalitat de Catalunya Grant No. 2009SGR1251. F. J. M. is thankful for the financial support from CICYT projects No. CSD2007-00045 and No. MAT2010-21270-C04-04, and the "Programa de Incentivo a la Investigacion" of the Universidad Politecnica de Valencia through project No. UPV2010-0096. A. H. R. has been supported by CONACyT Mexico under projects No. TAMU-Conacyt and No. J-83247-F. We acknowledge the beam time granted by ESRF.Serrano, J.; Bosak, A.; Krisch, M.; Manjón Herrera, FJ.; Romero, AH.; Garro, N.; Wang, X.... (2011). InN thin film lattice dynamics by grazing incidence inelastic x-ray scattering. Physical Review Letters. 106(20):2055011-2055014. https://doi.org/10.1103/PhysRevLett.106.205501S2055011205501410620Wu, J., Walukiewicz, W., Yu, K. M., Ager, J. W., Haller, E. E., Lu, H., … Nanishi, Y. (2002). Unusual properties of the fundamental band gap of InN. Applied Physics Letters, 80(21), 3967-3969. doi:10.1063/1.1482786Davydov, V. Y., Klochikhin, A. A., Seisyan, R. P., Emtsev, V. V., Ivanov, S. V., Bechstedt, F., … Graul, J. (2002). Absorption and Emission of Hexagonal InN. Evidence of Narrow Fundamental Band Gap. physica status solidi (b), 229(3), r1-r3. doi:10.1002/1521-3951(200202)229:33.0.co;2-oJones, R. E., Yu, K. M., Li, S. X., Walukiewicz, W., Ager, J. W., Haller, E. E., … Schaff, W. J. (2006). Evidence forp-Type Doping of InN. Physical Review Letters, 96(12). doi:10.1103/physrevlett.96.125505Song, J.-H., Akiyama, T., & Freeman, A. J. (2008). Stabilization of Bulkp-Type and Surfacen-Type Carriers in Mg-Doped InN{0001}Films. Physical Review Letters, 101(18). doi:10.1103/physrevlett.101.186801Qian, Z. G., Shen, W. Z., Ogawa, H., & Guo, Q. X. (2004). Experimental studies of lattice dynamical properties in indium nitride. Journal of Physics: Condensed Matter, 16(12), R381-R414. doi:10.1088/0953-8984/16/12/r01Davydov, V. Y., Emtsev, V. V., Goncharuk, I. N., Smirnov, A. N., Petrikov, V. D., Mamutin, V. V., … Inushima, T. (1999). Experimental and theoretical studies of phonons in hexagonal InN. Applied Physics Letters, 75(21), 3297-3299. doi:10.1063/1.125330Majumdar, A. (1993). Microscale Heat Conduction in Dielectric Thin Films. Journal of Heat Transfer, 115(1), 7-16. doi:10.1115/1.2910673Xu, K., & Yoshikawa, A. (2003). Effects of film polarities on InN growth by molecular-beam epitaxy. Applied Physics Letters, 83(2), 251-253. doi:10.1063/1.1592309Gonze, X., Beuken, J.-M., Caracas, R., Detraux, F., Fuchs, M., Rignanese, G.-M., … Allan, D. C. (2002). First-principles computation of material properties: the ABINIT software project. Computational Materials Science, 25(3), 478-492. doi:10.1016/s0927-0256(02)00325-7Gonze, X. (2005). A brief introduction to the ABINIT software package. Zeitschrift für Kristallographie - Crystalline Materials, 220(5/6). doi:10.1524/zkri.220.5.558.65066Gonze, X., Amadon, B., Anglade, P.-M., Beuken, J.-M., Bottin, F., Boulanger, P., … Zwanziger, J. W. (2009). ABINIT: First-principles approach to material and nanosystem properties. Computer Physics Communications, 180(12), 2582-2615. doi:10.1016/j.cpc.2009.07.007Troullier, N., & Martins, J. L. (1991). Efficient pseudopotentials for plane-wave calculations. Physical Review B, 43(3), 1993-2006. doi:10.1103/physrevb.43.1993Hartwigsen, C., Goedecker, S., & Hutter, J. (1998). Relativistic separable dual-space Gaussian pseudopotentials from H to Rn. Physical Review B, 58(7), 3641-3662. doi:10.1103/physrevb.58.3641Kim, K., Lambrecht, W. R. L., & Segall, B. (1996). Elastic constants and related properties of tetrahedrally bonded BN, AlN, GaN, and InN. Physical Review B, 53(24), 16310-16326. doi:10.1103/physrevb.53.16310Sarasamak, K., Limpijumnong, S., & Lambrecht, W. R. L. (2010). Pressure-dependent elastic constants and sound velocities of wurtzite SiC, GaN, InN, ZnO, and CdSe, and their relation to the high-pressure phase transition: A first-principles study. Physical Review B, 82(3). doi:10.1103/physrevb.82.035201Wright, A. F. (1997). Elastic properties of zinc-blende and wurtzite AlN, GaN, and InN. Journal of Applied Physics, 82(6), 2833-2839. doi:10.1063/1.366114Łepkowski, S. P., Majewski, J. A., & Jurczak, G. (2005). Nonlinear elasticity in III-N compounds:Ab initiocalculations. Physical Review B, 72(24). doi:10.1103/physrevb.72.245201Bungaro, C., Rapcewicz, K., & Bernholc, J. (2000). Ab initiophonon dispersions of wurtzite AlN, GaN, and InN. Physical Review B, 61(10), 6720-6725. doi:10.1103/physrevb.61.6720Manjón, F. J., Marí, B., Serrano, J., & Romero, A. H. (2005). Silent Raman modes in zinc oxide and related nitrides. Journal of Applied Physics, 97(5), 053516. doi:10.1063/1.185622

Electroluminescence of hot electrons in AlGaN/GaN high-electron-mobility transistors under radio frequency operation

Hot electrons in AlGaN/GaN high electron mobility transistors are studied during radio frequency (RF) and DC operation by means of electroluminescence (EL) microscopy and spectroscopy. The measured EL intensity is decreased under RF operation compared to DC at the same average current, indicating a lower hot electron density. This is explained by averaging the DC EL intensity over the measured load line used in RF measurements, giving reasonable agreement. In addition, the hot electron temperature is lower by up to 15% under RF compared to DC, again at least partially explainable by the weighted averaging along the specific load line. However, peak electron temperature under RF occurs at high VDS and low IDS where EL is insignificant suggesting that any wear-out differences between RF and DC stress of the devices will depend on the balance between hot-carrier and field driven degradation mechanisms