Effect Of The Ain Nucleation Layer Growth On Aln Material Quality

摘要

AlN layers were grown by metalorganic vapor-phase epitaxy at high temperatures up to 1500 ℃. Nucleation layer growth parameters and flow conditions before nucleation were changed and the effect on the AlN layer grown on top was studied. Structural analysis performed by high-resolution X-ray diffractometry and transmission electron microscopy showed that pregrowth conditions affect the material quality drastically. The best structural quality as indicated by a screw (including mixed) dislocation density of 8 × 10~8 cm~(-2), together with smooth surface morphology was found to result from simultaneous switching on of ammonia and TMA1 at the beginning of nucleation layer growth.