Low-temperature ion mixing of yttrium and silicon

Ion mixing of yttrium and amorphous silicon bilayers was measured as a function of fluence and temperature using 600-keV Xe⁺⁺ ions between 80 and 498 K. At 80 K the mixing rate was in excellent agreement with a theoretical model based on thermal spike mixing. For temperatures up to ≊372 K, the temperature-dependent contributions accounted for less than 50% of the overall mixing rate. For mixing at or above 400 K, our results revealed the formation of an ion-beam-induced orthorhombic Y-Si phase, which is not normally formed during thermal anneals of such bilayers.