Fabrication and characterisation of AlGaAs/InGaAs/GaAs pseudomorphic HEMT with in-situ epitaxial aluminium grown by MBE.

The fabrication and characterisation of AlGaAs/InGaAs/GaAs pseudomorphic HEMT (p-HEMT) with in-situ deposited epitaxial aluminium gate by MBE is reported. A simpler technique of fabricating HEMT without the inherent problem associated with gate recess is described. Its advantages over conventional method of fabricating HEMT are also shown. The near ideal epitaxial-Al/AlGaAs Schottky barrier contact is exploited in this work, resulting to an excellent I-V and thermal treatment characteristics. This epitaxial Al diodes have better ideality factor, higher barrier height and higher breakdown voltage but high series resistance than that of Au diodes.