Abstract

The interface formation mechanisms of AlN films on sapphire substrates grown by the elementary source vapor phase epitaxy (EVPE) method, which is a new AlN bulk fabrication method using Al and N₂ as precursors, are investigated. Supplying N₂ after the substrate temperature reaches the growth temperature [Process N₂(GT)] causes the interface to become rough due to the thermal decomposition of sapphire. Self-separation occasionally occurs with the Process N₂(GT), suggesting that the rough interface generates self-separating films with little strain. On the other hand, supplying N₂ beginning at room temperature forms a relatively smooth interface with voids, which can be realized by the reaction between a nitrided sapphire surface and an Al source. View Full-Text