Stability of interfaces in pseudomorphic InGaAs HEMTs

Considerable progress is now reported on pseudomorphic InGaAs high mobility transistors (PM. HEMTs). However, structures which exhibit the best performances are thermodynamically metastable. The stabilities of commercially available devices have been studied. Investigations of both GaAs InGaAs and AlGaAs/InGaAs interface vicinities have been performed through deep level characterizations. Life-testing experiments have then been carried out in order to assess the stability of the InGaAs buried strained layer and related interfaces during operation. Deep level studies together with electrical parameter measurements indicate that interfaces of InGaAs strained quantum well HEMTs do not induce particular degradations after 3000 hours into biased ageing tests.