Molecular beam epitaxial growth of high performance In 0.48Ga 0.52P/In 0.20Ga 0.80As/GaAs p-HEMTs using a valved phosphorus cracker cell

Abstract

In 0.48Ga 0.52P/In 0.20Ga 0.80As/GaAs pseudomorphic high electron mobility transistor (p-HEMT) structures were grown by solid-source molecular beam epitaxy (SSMBE) using a valved phosphorus cracker cell. The sheet carrier density at room temperature was 3.3×10 12 cm −2. A peak transconductance ( G m) of 267 mS mm −1 and peak drain current density ( I ds) of 360 mA mm −1 were measured for a p-HEMT device with 1.25 μm gate length. A high gate-drain breakdown voltage (BV gd) of 33 V was measured. This value is more than doubled compared to that of a conventional Al 0.30Ga 0.70As/In 0.20Ga 0.80As/GaAs device. The drain-source breakdown voltage (BV ds) was 12.5 V. Devices with a mushroom gate of 0.25 μm gate length and 80 μm gate width achieved a peak transconductance ( G m) of 420 mS mm −1 and drain current density of nearly 500 ma/mm. A high cut-off frequency ( f T) of 58 GHz and maximum oscillation frequency ( f max) of 120 GHz were obtained. The results showed that the In 0.48Ga 0.52P/In 0.20Ga 0.80As/GaAs material system grown by SSMBE using the valved phosphorus cracker cell for the In 0.48Ga 0.52P Schottky and spacer layers is a viable technology for high frequency p-HEMT device applications. The performance of the 0.25-μm gate length device was simulated using a two-dimensional device simulator, MEDICI®, which incorporates physical models such as Shockley–Read Hall recombination, Auger recombination, Fermi-Dirac statistics and field-dependent mobility.