Homogeneous high In content InxGa1−x N films by supercycle atomic layer deposition

Abstract

InxGa1−x N is a strategically important material for electronic devices given its tunable bandgap, modulated by the In/Ga ratio. However, current applications are hindered by defects caused by strain relaxation and phase separation in the material. Here, we demonstrate growth of homogeneous InxGa1−x N films with 0.3 < x < 0.8 up to ∼30 nm using atomic layer deposition (ALD) with a supercycle approach, switching between InN and GaN deposition. The composition is uniform along and across the films, without signs of In segregation. The InxGa1−x N films show higher In-content than the value predicted by the supercycle model. A more pronounced reduction of GPCInN than GPCGaN during the growth processes of InN and GaN bilayers is concluded based on our analysis. The intermixing between InN and GaN bilayers is suggested to explain the enhanced overall In-content. Our results show the advantage of ALD to prepare high-quality InxGa1−x N films, particularly with high In-content, which is difficult to achieve with other growth methods.