InGaAs/InP double channel HEMT on InP

Abstract

The authors discuss a novel HEMT (high electron mobility transistor) channel structure, consisting of InGaAs and InP, which can utilize both the high electron mobility of InGaAs at low electric field and InP's high drift velocity at high electric field. HEMTs with 0.6- mu m gates, a double channel, and a planar doped carrier supply layer show an extremely high transconductance of 1290 mS/mm. Such a device with a 0.7- mu m gate has a cutoff frequency of 68.7 GHz, which exceeds that of conventional InGaAs HEMTs by a factor of 1.3. It is shown that these characteristics may be related to an increase of the effective saturation velocity of electrons in the channel from 2.7*10/sup 7/ cm/s to 4.2*10/sup 7/ cm/s. Moreover, it is found that there is no kink in the I-V characteristics of double channel devices. These results indicate that InGaAs/In double-channel HEMTs have great potential for application in high-speed and high-power devices.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>