Breaking the millimeter-wave frequency barrier

It is predicted that antimonide-barrier HEMTs (high electron mobility transistors) with 100% InAs channels will exhibit terahertz maximum operating frequencies and significantly lower noise figures for the same dimensions. Device structures with n-AlSb barriers and undoped InAs channels have been grown by molecular beam epitaxy on GaAs and InP substrates. The larger saturated drift velocity of InAs and less scattering than InGaAs provides higher cutoff frequency and lower noise figure. The advantage is much greater than can be achieved by shrinking dimensions and/or parasitic losses of PM InP devices. Potential applications include the next generation of advanced MMICs (monolithic microwave integrated circuits) for use in smart weapons, deep space communication, earth sensing, and imaging systems operating at deep mm-wave and sub-mm-wavelengths.<
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