New self-aligned T-gate InGaP/GaAs field-effect transistors grown by LP-MOCVD

This paper reports on self-aligned T-gate InGaP/GaAs FETs using n/sup +//N/sup +///spl delta/(P/sup +/)/n structures. N/sup +/-InGaP//spl delta/(P/sup +/)-InGaP/n-GaAs forms a planar-doped barrier. The inherent ohmic gate of camel-gate FETs together with a highly selective etch between an InGaP and a GaAs layers offers a self-aligned T-shape gate with a reduced effective length. A fabricated device with a reduced gate dimension of 1.5×100 (0.6×100) μm2obtained from 2×100 (1×100) μm2gate metal exhibits an extrinsic transconductance, unity-current gain frequency, and unity-power gain frequency of 78 (80) mS/mm, 9 (19.5), and 28 (30) GHz, respectively.