WereportonanimprovementforthecrystalqualityofN-polarGaNwithapseudomorphicalygrown graded-Al-fractionAlGaNinterlayerwhichintroducesstrainmanagementinheterostructureandbrings in theinclinationandannihilationofthreadingdislocations(TDs).Significant blockingofscrewandedge component TDsareobs