ABSTRACT
Strained layer InxGai_xAs/GaAs systems have received a great deal of attention in the last few years due to their potential applications to electronic and opto-electronic semiconductor devices. The InxGai_xAs alloy layer is biaxially compressed due to the larger lattice constant compared to the GaAs layer. Despite the fact that the alloy layer is under high strain (from 0 to 7%), high quality of epitaxial layers can be obtained (see [1] and references therein). The InxGai_xAs alloy band gap is smaller than the GaAs one resulting in higher potential barrier between InxGai_xAs and AlvGai_ vAs heterojunctions when compared to the GaAs/AlvGai_ vAs based systems. This change in the band structure becomes useful for applications in high
speed digital and optical devices, such as high electron mobility transistors (HEMT) [2-5] and quantum well laser diodes [6-11]. The advance of crystal growth techniques enabled the fabrication of semiconductor devices with multi-layered materials. The fabrication steps of these devices involves unintentional annealing processes during impurity diffusion and electric contact metal deposition. In quantum well and superlattice based devices, the intermixing of atoms at the interface during the thermal annealing can change the band structure potential profile, affecting the device properties and their performance.
