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

GaN-based HEMTs on Low Resistivity Silicon Technology for Microwave Applications

This paper investigates the effect of insertion AlN spacer between the GaN channel and buffer in a sub-micron gate (0.3 μm) AlGaN/GaN HEMTs on a low-resistivity (LR) (σ < 10 Ω.cm) silicon substrates on RF performance. Enhancement in short circuit current gain (fT) and maximum frequency of oscillation (fMAX) was observed in the HEMT with a 1 nm AlN spacer, where (fT) and (fMAX) were increased from 47 GHz to 55 GHz and 79 GHz to 121 GHz, respectively. Small-signal-modelling analysis was carried out to study this improvement in performance. We found that the AlN interlayer played a crucial role in reducing the gate-source capacitance, Cgs, by 36 % and delay, τ, by 20 % under the gate, as a result of an increase in mobility and a reduction in trap-related effects