The influence of the momentum transfer on the structural and optical properties of ZnSe thin films prepared by r.f. magnetron sputtering

ZnSe films were deposited at room temperature by radio frequency magnetron sputtering onto [100] oriented silicon substrates. Under the same depositio n conditions three sets of samples were produced by varying the sputtering pressure (0.4, 0.5 and 0.9 Pa), and changing the sputtering power supply in the range 25-150 W. The effect of the different growth conditions on the s tructural and optical properties was investigated by using X-ray diffractio n (XRD) and Fourier transform infrared (FTIR) Spectroscopy. In particular, the dependence of the coatings residual strain, texture, refractive index a nd extinction coefficient on the parameter beta, proportional to the moment um transfer was studied. According to the results, the ZnSe coatings were g rown almost exclusively in the cubic phase with a small percentage of very disordered ZnSe hexagonal phases. At low beta values, the films were found in a tensile in-plane stress state, then a stress inversion from tensile to compressive occurred at beta = 27 a.u. and the films remained in a compres sive state for momentum values beta > 27 a.u. (C) 2000 Elsevier Science S.A . All rights reserved.