Degradation-free modulation-doped field-effect transistors grown by organometallic chemical vapor deposition

Using AlGaAs and GaAs grown by organometallic chemical vapor deposition (OMCVD), we have fabricated high-transconductance modulation-doped field-effect transistors which do not exhibit the severe electrical degradation in the dark at 77 K that is ordinarily observed in such devices. Such degradation has been attributed to defects in the n+-AlGaAs. Experiments on ohmic test devices using different OMCVD grown structures suggest that the improvement is due to a drastically reduced charge polarization in the n+-AlGaAs layer.