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采用脉冲激光沉积(PLA)法,在单晶Si试样表面沉积制备了一系列TiN/AlN硬质多层膜,并采用基于免疫算法的免疫径向基函数(IRBF)神经网络对AlN厚度建立预测模型,设计出具有可控调制周期和调制比的TiN/AlN多层膜。X射线衍射(XRD)结果表明,小调制层周期下,过高或过低的工艺条件下薄膜通常为非晶态,适当的工艺条件下TiN、AlN形成具有强烈织构的超晶格柱状晶多层膜;与此相应,纳米多层膜产生了硬度和弹性模量异常增高;随着调制比增加,使纳米多层膜形成非晶AlN层和纳米晶TiN层的多层结构,多层膜的硬度和弹性模量逐渐下降。XPS结果表明,薄膜界面由Ti+4、Ti+3离子组成,N的负二价、三价亚谱结构预示着非当量TiN、AlN的形成。AFM研究显示,薄膜的调制周期均在10~200 nm范围内,且薄膜表面较均匀;当多层薄膜调制周期在50 nm以下时,薄膜的纳米硬度值明显高于TiN和AlN的混合硬度值,达30 Gpa。
A series of TiN / AlN hard multilayers were deposited on the surface of single-crystal Si samples by pulse laser deposition (PLA) method. The AlN thickness was established by immune radial basis function (IRBF) neural network based on immune algorithm The model was predicted to design a TiN / AlN multilayers with controlled modulation period and modulation ratio. The results of X-ray diffraction (XRD) show that the thin films are usually amorphous under the condition of too low or too low cycle under the small modulation layer period. TiN and AlN are formed into super-textured columnar crystals with strong texture under appropriate process conditions Multi-layer film; correspondingly, the nano-multi-layer film has an abnormally high hardness and elastic modulus; as the modulation ratio increases, the multi-layer film is formed into a multi-layer structure of an amorphous AlN layer and a nanocrystalline TiN layer, Film hardness and elastic modulus decreased gradually. XPS results show that the interface of the film is composed of Ti + 4 and Ti + 3 ions, and the negative divalent and trivalent sub-spectral structures of N indicate the formation of non-equivalent TiN and AlN. AFM showed that the modulation period of the films was in the range of 10-200 nm and the surface of the film was uniform. When the modulation period of the multilayer films was below 50 nm, the nano-hardness of the films was significantly higher than that of TiN and AlN , Up to 30 Gpa.