Characterization of deep level traps in ultrasubmicron modulation-doped field-effect transistors on InP substrate using improved photo-induced current spectroscopy (PICS)

We have used a previously developed improved photo induced current spectroscopy (PICS) technique to scan the optical activation energies of electron and hole traps in 0.15/spl mu/m x 50/spl mu/m gate-area MODFET's based on InP substrate. For comparison purposes we have also examined the traps in a conventional AlGaAs/GaAs MODFET. Measurements with a constant low-drain voltage (/spl les/ 40mV), with and without a pre-pulsed higher drain voltage, are performed to explore the possible presence of traps in the channel and buffer layers. Results of determination of optical and thermal activation energies are presented for comparison.