Résumé
The monolithic integration of GaSb-based optoelectronic devices on Si has emerged as apromising solution for achieving low-cost, compact, and scalable infrared photonics integrated circuits(PICs) [1]. However, the III-V growth on Si involves a lattice mismatch which leads to a high densityof threading dislocations (TDD), responsible for non-radiative recombination, and deteriorating laseroperation [2]. Therefore, our goal is to reduce the defect density while keeping the overall structure asthin as possible. Previous studies used thermal cycling annealing (TCAs) [3], strained layersuperlattice(SLS) [4] or defect filter layers (DFLs) [5] to reduce the TDD. In this work, we studied anapproach combining an AlSb single insertion layer (SIL), as previously reported [5], and annealing,because thermal strain also provides energy for dislocations to move, react and annihilate.We will show the impact of the SIL thickness and strain on the TDD (Fig.1). Then, we will present thebest annealing conditions (Fig.1). Upon careful analysis of the growth parameters, we demonstrate aTDD of 3.1 × 107cm-2 for a 1.6 μm thick GaSb buffer layer grown on Si, i.e. a thickness more thantwice smaller than previous reports [6,7]. Finally, using Electron Channelling Contrast Imaging (ECCI)and Transmission Electron Microscopy (TEM), we extensively studied the dislocation networks formedat each AlSb interface (Fig.2) and we propose a strain relaxation mechanism based on dislocation glide.