| AVS 63rd International Symposium & Exhibition | |
| Thin Film | Friday Sessions |
| Session TF-FrM |
| Session: | CVD, ALD and Film Characterization |
| Presenter: | Fahad Althowibi, University of Connecticut |
| Authors: | F. Althowibi, University of Connecticut J.E. Ayers, University of Connecticut |
| Correspondent: | Click to Email |
Pseudomorphic high-electron mobility transistors (HEMTs) are of great of interest for high-frequency applications. One approach to pseudomorphic transistors involves a superlattice structure, thereby decreasing the individual active layer thicknesses and extending the range of composition for pseudomorphic realization. Generally, X-ray characterization of pseudomorphic HEMTs is difficult to implement due to the complexity of the resulting diffraction profiles. In this work we show for the first time that superlattice implementation of HEMTs aids in the characterization of the pseudomorphic/metamorphic transition by x-ray diffraction means.
Here we report a study of the dynamical x-ray diffraction from GaAs/In0.3Ga0.7As superlattice high electron mobility transistor heterostructures on GaAs (001) substrates both with (metamorphic) and without (pseudomorphic) dislocations. We show that the threading dislocation density may be estimated from non-destructive x-ray rocking curve measurements, using the rocking curve peak intensity ratios and widths for superlattice diffraction peaks. Here, the peak widths are obtained from the broadening of the individual rocking curve peaks, while the reduction in peak intensity values may be also used to serve as a sensitive tool for the characterization of threading dislocations. These approaches therefore allow characterization of HEMT structures as pseudomorphic or metamorphic.