7 October 2015

IQE's GaN-on-SiC epiwafers used to achieve record power and frequency results for satcom and 5G applications

Epiwafer foundry and substrate maker IQE plc of Cardiff, Wales, UK has been acknowledged for supplying commercially ready 100mm gallium nitride on silicon carbide (GaN-on-SiC) epiwafers that were used to produce record results for both high-gain and high-power-density transistor devices, enabling - for the first time - a flexible monolithic microwave integrated circuit (MMIC) design for efficient high-voltage/high-power broadband operation at frequencies ranging at 0–40GHz (Fitch et al, 'Implementation of High-Power-Density X-Band AlGaN/GaN High Electron Mobility Transistors in a Millimeter-Wave Monolithic Microwave Integrated Circuit Process', IEEE Electron Device Letters, vol 36, no. 10, October 2015).

The high-electron-mobility transistor (HEMT) devices were produced using GaN-on-SiC wafers purchased from IQE by the US Air Force Research Laboratory (AFRL), Sensors Directorate, Aerospace Components Division, Devices for Sensing Branch at Wright-Patterson Air Force Base in Dayton, OH.

High-frequency microwave capabilities of up to 40GHz (the Ka-band) are essential for satellite communications and will become increasingly important for next-generation (5G) wireless communicationsnotes IQE. However, until now, designers have faced compromises between frequency and power.

The solution outlined in the paper provides designers with the option of incorporating two different devices by implementing a 0.14μm-gate-length GaN MMIC process capable of high-efficiency Ka-band operation while simultaneously achieving high-power-density X-band operation using the same process flow.

The authors demonstrated power density of 7.7W/mm at 35GHz and drain bias of VDS = 30V on a standard 4 × 65μm T-gated FET and then 12.5W/mm at 10GHz and VDS = 60V on a 4 × 75μm T-gated FET by adding a field plate. These are said to be the highest reported power densities achieved simultaneously at X-band and Ka-band in a single wideband GaN MMIC process.

The epiwafers were produced at IQE's New Jersey facility using metal-organic chemical vapor deposition (MOCVD) on 4′" semi-insulating SiC substrates.

"These results, achieved on our GaN-on-SiC epiwafers, demonstrate the ability of IQE to produce record-breaking, world-leading results on commercial platforms that enable today's leading-edge satellite communications and will be essential for enabling next-generation wireless technologies," says Dr Wayne Johnson, VP of IQE's Power Business Unit.

Tags: IQE GaN-on-SiC HEMT

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