Correlation between hot-electron-stress-induced degradation and cathodoluminescence in InP based HEMTs

Low temperature spectrally resolved Cathodoluminescence has been used to study the effects of electrical degradation induced by hot-electron-stress on the optical transitions in lattice matched InAlAs/InGaAs/InP HEMTs. A clear reduction of the cathodoluminescence emission collected from the gate-drain region of stressed devices has been found, indicating a modification of the trap density inside the device. Depth resolved analyses from the gate-drain region before and after stress evidenced that the electric field due to the traps induced by the hot-electron-stress mainly influenced a device region between the highly doped InAlAs and InGaAs cap layers and the n+ doped donor and undoped spacer InAlAs layers. The effect of the hot electron stress has been evidenced mainly on the catodoluminescence transitions from the InAlAs layers. No evidence of a possible influence on the intrinsic InGaAs channel has been found.