Structure of A1N on Si (111) deposited with metal organic vapor phase epitaxy

Abstract

The surface morphology and structure of AlN deposited by metal organic vapor phase epitaxy (MOVPE) on Si (111) at growth temperatures ranging from 825 to 1175°C was investigated. Transmission electron microscopy (TEM), reflection high energy electron diffraction (RHEED), atomic force microscopy (AFM), and secondary ion mass spectrometry (SIMS) techniques were used to study the resulting film structure. Growth at high temperatures but less than ∼1100°C, resulted in a wire texture with some degree of in-plane alignment with (0001) AlN//(111) si′, 〈10̄10〉 AlN//〈211〉 Si, and 〈1120〉 AlN // 〈110〉 Si. Deposition at temperatures greater than 1100°C results in single crystal films consisting of domains 60 nm across with an aspect ratio near unity. Growth below 1100°C leads to degraded crystal quality with the grains developing random rotational misalignments around the AlN [0001] axis. Growth at lower temperatures produces islands elongated along the [1120] direction. At the growth temperature of 825°C, the aspect ratio of the islands increased to 3 and a width of 25 nm. Cross-sectional TEM reveals that these islands are faceted due to slow growth on the {1̄101} planes.