When talking about 5G, what role do you expect gallium-nitride (GaN) technology to have?
Peterson: The primary role for GaN, or more specifically, GaN-on-silicon-carbide (GaN-on-SiC), is high-efficiency final stage power amplifiers (PAs) for both traditional high-power macro, as well as emerging massive MIMO base station platforms. Widespread market adoption for GaN-on-SiC power amplifiers has been driven by the demand for wider-bandwidth multi-carrier and multi-band systems. Systems that once covered a single 20-MHz bandwidth now need 10x the power and 20x bandwidth to handle various intraband and interband carrier aggregation combinations.
It is generally accepted that GaN-on-SiC Doherty PAs achieve higher power-added efficiency (PAE) at higher frequencies and over larger bandwidth compared to incumbent LDMOS technology. At a unit-cell level, GaN devices are fundamentally more efficient and inherently have higher output impedance, along with lower parasitic capacitance. This allows easier wideband matching and scaling to very large output powers. In addition, GaN-on-SiC is more reliable at high channel temperatures. The bottom line is that GaN is a fundamentally better semiconductor (high breakdown voltage and saturation velocity) that allows new system level trades to improve size, weight, power, and cost.