State of this art performance was obtained on AlGaN/GaN HEMT grown on silicon (111) substrate by molecular beam epitaxy. A maximum DC current density of 1.1 A.mm-1 and a peak extrinsic transconductance of 374mS.mm-1 are obtained for 75nm gate length device. At VDS=25V, continuous wave output power density of 2.7W.mm-1 is achieved at 40GHz associated with 12.5% power-added efficiency and a linear power gain of 6.5dB (Fig.3a). The device exhibits an intrinsic current gain cutoff frequency fT of 116GHz and a maximum oscillation frequency fmax of 150GHz [1]. On silicon (110) substrate, maximum DC current density of 1.67 A.mm-1 and a peak extrinsic transconductance of 595mS.mm-1 are obtained for 60nm gate length device. At VDS=15V, continuous wave output power density of 3.3W.mm-1 is achieved at 40GHz associated with 20.1% power-added efficiency and a linear power gain of 10.6 (Fig.3b). The device exhibits an intrinsic current gain cutoff frequency fT of 108GHz and a maximum oscillation frequency fmax of 167GHz [2].
Fig.3a: Output power, power gain and power added efficiency versus injected power at 40 GHz for a 2×50×0.075 μm2 AlGaN/GaN HEMT on Si(111) substrate at VDS=25V
Fig.3b: Output power, power gain and power added efficiency versus injected power at 40 GHz for a 2×30×0.06 μm2 AlGaN/GaN HEMT on Si(110) substrate at VDS=15V
[1] ALTUNTAS P. et al, IEEE Electron Device Letters, Vol.36, n°4, pp.303-305, April 2015
[2] SOLTANI A.et al, IEEE Electron Device Letters, Vol.34, n°4, pp.490-492, April 2013
