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采用纳米压痕方法,研究了AlN/spphire模板上的高Al组分AlxGa1-xN薄膜的力学性质,特别是弹性-塑性转变行为.研究表明,AlxGa1-xN薄膜的杨氏模量E随着Al组分的增加而增大,薄膜中产生塑性形变所必要的剪切应力也随着Al组分的增加而增大.在AlxGa1-xN薄膜纳米压痕实验中,观察到位移不连续的跳断(“pop-in”)行为,并且发现“pop-in”行为强烈依赖于Al组分,Al组分的增加导致这种行为的减少.我们认为随着Al组分的增加,AlxGa1-xN中键能的增强和由于AlxGa1-xN与AlN/sapphire模板之间晶格失配减少这两个因素增加了AlxGa1-xN中新位错形成的阻力,从而导致了AlxGa1-xN薄膜中的“pop-in”行为随Al组分增加而减少.
The mechanical properties of AlxGa1-xN thin films on AlN / spphire template, especially the elastic-plastic transition behavior, were investigated by nano-indentation method.The results show that the Young’s modulus E of AlxGa1-xN thin films increases with Al The increase of the composition increases the shear stress necessary to produce plastic deformation in the film also increases with the increase of Al composition.In the AlxGa1-xN thin film nanoindentation experiment, the discontinuous displacement discontinuity was observed (“pop-in”) behavior and found that the behavior of “pop-in ” strongly depends on the Al component and the increase of Al component leads to a decrease of this behavior.We think that with the increase of Al component, The enhancement of the central energies in AlxGa1-xN and the reduction of lattice mismatch between AlxGa1-xN and AlN / sapphire templates increase the resistance to the formation of new dislocations in AlxGa1-xN, resulting in The “pop-in” behavior decreases with increasing Al composition.