A novel method of structure control in Si thin film technology

A technological method of thin film silicon growth with an unconventional structure control has been uncovered. It involves a concurrence of metal-induced crystallization with direct growth of crystalline silicon at temperatures of ca. 575°C. Thermally evaporated 5-100 nm thick Ni films were used as prelayers for magnetron sputtered Si films. The thickness of a Ni prelayer was established to significantly alter the silicon film growth, providing a large-grain columnar structure when occurring in the 25-30 nm range, and diminishing the Si grain size toward corresponding lower and higher values of the Ni thickness. The phenomenon is attributed to the silicide nucleation processes at the Ni-Si interface. A decrease in the kinetic energy of the arriving Si atoms accomplished by lowering the magnetron power led to the formation of self-organized nanostructures on the Si film surface suggesting the Stranski-Krastanov growth mode which is also induced by the Ni suicide prelayer. Theoretical aspects of Si film growth are briefly discussed.