Stress relaxation by surface rippling and dislocation generation in mismatched channels of InGaAs/InAlAs/InP high-electron-mobility transistors

We have investigated InGaAs strained channels of high-electron-mobility transistor heterostructures with In compositions of 70% and 80% and channel thicknesses covering the range of 3–14 nm. Transmission electron microscopy characterization has revealed the existence of two regimes of strain relaxation in these strained InGaAs channels: (i) an anisotropic rippling of the channel surface at low mismatch and (ii) dislocation generation as the layer thickness and mismatch increase. The correlation of structural features with electrical measurements has provided evidence of a significant reduction of the Hall mobility values measured across the rippling of the InGaAs well. © 1999 American Institute of Physics.