Electron transport in 0.15- mu m gate In/sub 0.52/Al/sub 0.48/As/In/sub 0.53/Ga/sub 0.47/As HEMT

Magneto-transport and cyclotron resonance measurements were made to determine directly the density, mobility, and the effective mass of the charge carriers in a high-performance 0.15- mu m gate In/sub 0.52/Al/sub 0.48/As/In/sub 0.53/Ga/sub 0.47/As high-electron-mobility transistor (HEMT) at low temperatures. At the gate voltage V/sub G/=0 V, the carrier density n/sub g/ under the gate is 9*10/sup 11/ cm/sup -2/, while outside of the gate region n/sub g/=2.1*10/sup 12/ cm/sup -2/. The mobility under the gate at 4.2 K is as low as 400 cm/sup 2//V-s when V/sub G/<0.1 V and rapidly approaches 11000 cm/sup 2//V-s when V/sub G/>0.1 V. The existence of this high mobility threshold is crucial to the operation of the device and sets its high-performance region in V/sub G/>0.1 V.<
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