Novel pseudomorphic InP/InAs/sub 0.6/P/sub 0.4/ quantum-well HEMT's

The authors report the first investigation of the transport properties of a 2DEG in pseudomorphic InP/InAs/sub x/P/sub 1-x/ modulation-doped heterostructures and the device characteristics of HEMTs (high electron mobility transistors) with an InP/InAs/sub 0.6/P/sub 0.4/ quantum-well channel. The dependence of the low- and high-field transport properties on the arsenic composition (x) has been studied. The Hall mobility for x=0.6 was measured to be 6100 and 52700 cm/sup 2//V-s at 300 and 77 K, respectively. The FETs having a gate length of 0.5 mu m exhibited a maximum external transconductance of 320 mS/mm and a drain saturation current density of 705 mA/mm. The f/sub T/ and f/sub max/ were measured to be 55 and 60 GHz, respectively. The saturation electron velocity was estimated to be 2.1*10/sup 7/ cm/s. The results clearly demonstrate the great potential of these material systems for high-speed applications.<
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