Journal Article Effects of Al and N2 flow sequences on the interface formation of AlN on sapphire by EVPE

Kishimoto, Katsuhiro  ,  Funato, Mitsuru  ,  Kawakami, Yoichi

7 ( 5 ) 2017-04-27 , MDPI AG
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.

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