Microstructure Characterization Of Cr-based Metal And Nitride Nanometer-scale Multilayers

Fe/Cr and CrN/AIN are the two finds of Cr-based nanometer-scale multilayers deposited by direct current magnetron sputtering magnetron sputtering method onto single crystal Si(100) and AISI304 stainless steel substrates with a base pressure better than 2×10-5 Pa, and the working pressure of 0.3 Pa. The nominal modulation wavelengths range of Fe/Cr nanometer-scale multilayers are from 10.0 to 100.0 nm, and the target power of Fe and Cr are both 100 W, the sputtering gas is research-grade Ar. The nominal modulation wavelengths range of CrN/AIN nanometer-scale multilayers are from 3.0 to 4.0 nm, and the target power of Cr and Al are both 100 W, the sputtering gas is mixture of Ar and N2 with ratio of 1:1. The alternating sublayers thickness ratios of two kinds of nanometer-scale multilayers are both 1:1. Modulation structures are characterized by using Rutherford backscattering spectroscopy (RBS), small angle/wide angle x-ray diffraction (SA/WAXRD) and high resolution transmission electron microscopy (HRTEM).The actual modulation wavelengths of Fe/Cr nanometer-scale multilayers are 11.0,20.0, 53.6 and 103.6 nm with the design value of deviation of 10.0%,0,7.2%and 3.6%, and the actual sublayers thickness ratios are close to 1:1. The modulation interfaces are clear. With the smaller modulation wavelength of 11.0 nm, the Fe/Cr nanometer-scale multilayer consists of long columnar gains which extend over the coating thickness with the width of 20-50 nm. A preferred orientation of (110) was detected in a-Fe and a-Cr with coherent interface. When the modulation wavelength was increased till 103.6 nm, the preferred orientation of Fe/Cr nanometer-scale multilayers were changed to (002) and the disconnected columnar gains with the width of 50-100 nm were observed in the Fe and Cr sublayers, respectively. It is found that the existence of coherence interface with high interface energy benefits to the formation of (110) preferred orientation in the Fe/Cr nanometer-scale multilayers.The actual modulation wavelengths of CrN/AIN nanometer-scale multilayers are 3.1 and 3.9 nm, and the actual sublayers thickness ratios are close to 1:1 with the design value of deviation of 3.3%and 2.5%. The CrN/AIN nanometer-scale multilayers consist of long columnar gains which extend over the coating thickness with the width of 30-80 nm. The modulation interfaces are clear with wavy distribution. CrN and AIN sublayers are composed with NaCl-type crystal structure single fcc phase. The thickness of AIN sublayer is the key factor for AIN sublayer tending to an unstable structure of fcc phase. The crystal structure, preferred orientation in sublayers of thin-films and modulation interfaces are significantly influenced by the modulation structure of the nanometer-scale multilayers.