Defect annihilation in AlN thin films by ultrahigh temperature processing

摘要: Postgrowth thermal processing in the range of 1200–1400 °C is shown to improve markedly quality thin (∼200 nm) AlN films grown by molecular beam epitaxy on SiC substrates. Comparison both on-axis (0002) and off-axis (1012) x-ray diffraction peaks documents this improvement. Cross-sectional transmission electron micrographs confirm reduction dislocations grain boundaries, while plan-view demonstrate that threading defect densities can be reduced ∼3×108/cm2 after annealing. The treatment particularly effective because unusually large temperature window between onset a near-zero reactant sticking coefficient at ∼1200 °C decomposition ∼1400 °C. Al rate are also reported.