INP-BASED HEMTS WITH AL0.48IN0.52AS(X) P(1-X) SCHOTTKY LAYERS

In this letter we report on the dc and RF performance of InP-based HEMT's with Al0.48In0.52AsxP1-x Schottky layers and GaInAs/InP composite channels. By replacing the Al0.48In0.52As Schottky layer with Al0.48In0.52AsxP1-x we have been able to increase the bandgap of the Schottky layer and achieve record breakdown voltages for 0.15 mum gate-length InP-based HEMT's. The 0.15 mum gate-length HEMT's have gate-to-drain breakdown voltages of over 13 V with current densities of 620 mA/mm and maximum transconductances of 730 mS/mm. On a wafer with a higher sheet charge we have obtained gate-to-drain breakdown voltages of 10.5 V with current densities of over 900 mA/mm. These are the highest breakdown voltages reported for 0.15 mum gate-length InP-based HEMT's with such high current densities. At 10 GHz a 450 mum wide HEMT has demonstrated 350 mW (780 mW/mm) of output power with power-added efficiency of 60% and 12 dB gain.