Wideband power amplifier MMICs utilizing GaN on SiC

Advanced thermal management technologies for defense electronics

“…Current GaN PAs are often fabricated on SiC substrates, which have provided improved thermal management capability compared to Si and sapphire substrates, but GaN power amplifier devices remain thermally limited and fielded devices cannot reach sustained operation at the reported device technology limits. [44,45]. To reduce the dominant thermal resistance in these GaN devices, the NJTT program addresses thermal transport in the region within 100 μm of the transistor junction, or the "near-junction" region, where the local heat flux in the epitaxial layers just below the gate can exceed that encountered on the surface of the sun [46].…”

GaN HEMT: Dominant Force in High-Frequency Solid-State Power Amplifiers

“…It is interesting to compare the GaN HEMT benchmarks [30], [31] with PHEMT [32] as it illustrates the circuit advantages of GaN HEMT. Because of the Pout versus impedance tradeoff described earlier, the GaN HEMT MMICs have a higher Pout (10-20 W versus 4-5 W), a wider bandwidth (2-20 GHz versus 4-18 GHz), and a higher efficiency (26% versus 23% average).…”

High power K-band GaN on SiC CPW monolithic power amplifier

“…The heterostructure of the active devices is grown using metal organic chemical vapor deposition (MOCVD) on 2-inch semi-insulating SiC substrates due to very high thermal conductivity of SiC [5,8]. Fabrication process consists of mesa etching to isolate the active devices, followed by formation of Ti/Al/Ni/Au (120 Å /1200 Å /350 Å /650 Å) ohmic contacts for drain and source contacts.…”