Embodiments of the present disclosure relate to reducing dislocation density in a heteroepitaxial growth film and devices including heteroepitaxial films with reduced dislocation density. According to embodiments of the present disclosure, sidewalls of high aspect ratio trenches may be tilted or angled to allow defects in crystalline material formed in the high aspect ratio trenches to be terminated in the tilted sidewalls, including defects propagating along the length of the high aspect ratio trenches. Embodiments of the present disclosure may be used to reduce defects in heteroepitaxial growth on silicon (Si) for microelectronic applications, such as high mobility channels using Group III-V elements in field effect transistors.