(鄭州大學(xué) 物理學(xué)院(微電子學(xué)院)，鄭州 450052)
摘 要: 采用分子動力學(xué)模擬澆鑄法制備的銅/鋁/銅三層膜在循環(huán)載荷作用下的變形過程，分析孔洞的演化機(jī)理。結(jié)果表明：鋁薄膜的中部和界面處靠近鋁側(cè)出現(xiàn)孔洞。鋁薄膜中部的孔洞演化為：壓桿位錯被克服，出現(xiàn)空隙；形核處新產(chǎn)生的壓桿位錯被克服，空隙長大。數(shù)次發(fā)射位錯環(huán)，空位團(tuán)長大形成孔洞；孔洞形核附近退孿晶形成層錯，應(yīng)力釋放，孔洞長大；應(yīng)力集中、釋放使得層錯消失、出現(xiàn)，孔洞進(jìn)一步長大；孔洞形核附近的層錯發(fā)生交截，且在形核處發(fā)射位錯，使得孔洞長到最大。壓縮力下，孔洞被無序結(jié)構(gòu)原子填充，沿應(yīng)變加載方向縮小。無序結(jié)構(gòu)原子填充孔洞，孔洞閉合。界面處靠近鋁側(cè)孔洞的演化為：壓桿位錯被克服，出現(xiàn)空隙。應(yīng)變增加，HCP結(jié)構(gòu)的原子轉(zhuǎn)換為無序結(jié)構(gòu)的原子，空隙沿應(yīng)變加載方向長大，形成孔洞。隨著加載的進(jìn)行，層錯出現(xiàn)，應(yīng)力釋放，孔洞隨之增大。隨著應(yīng)變的繼續(xù)增加，孔洞沿應(yīng)變加載方向縮小，無序結(jié)構(gòu)原子填充孔洞；周圍無序結(jié)構(gòu)原子轉(zhuǎn)化為FCC結(jié)構(gòu)原子，孔洞閉合。
關(guān)鍵字: 分子動力學(xué)；銅/鋁/銅三層膜；循環(huán)載荷；孔洞
（School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China）
Abstract:The molecular dynamics method was used to simulate the deformation process of the Cu/Al/Cu three-layer film prepared by the casting method under cyclic loading, the evolution process of void was analyzed. The results show that the voids appear at the middle of the Al film and the interface near the Al film side. The evolution process of the void at the middle of the Al film is as follows: the Hirth dislocation and Stair-rod dislocation at the middle of the Al film are overcome, allowing the gaps to grow. Then, launching the dislocation loop several times at the void nucleation, the vacancy group grows and forms the void. Detwinning crystal forms a stacking fault, releasing the stress and allowing the void to grow. The stress concentration and release make the stacking fault disappear and reappear, and then, the void further grows. The stacking faults near the void nucleation are intercepted, and the dislocation are emitted at the void nucleation, and the void grows to the maximum. Under the compressive force, the void is filled by atoms with other structure, which shrinks into a vacancy cluster along the strain loading direction. The void is filled by atoms with other structure, and closes. The evolution process of the void near the Al side at the interface is as follows: Hirth dislocations and Stair-rod dislocations are overcome, and a gap appears. As strain increases, the atoms of the HCP structure at the nucleation of the void are converted to the atoms with the other structure, and the gap grows along the strain loading direction to form the void. The stacking faults appear, the stress is released, and the void grows with strain loading. Continue to load, and the void shrinks into vacant cluster along the strain loading direction, and the atoms of other structure fill the void. The atoms of other structure around the void are converted to atoms of FCC structure, so void closes.
Key words: molecular dynamics; Cu/Al/Cu three-layer film; cyclic load; void
