Crystallization Behavior and Thermal Analysis of CoFeB Thin Films

We examined two targets containing Co40Fe40B20 and Co60Fe20B20. We deposited Co40Fe40B20 and Co60Fe20B20 monolayer thin films of various thicknesses on glass substrates through DC magnetron sputtering; the thicknesses ranged from 25 to 200 Å. The thermal properties of the Co40Fe40B20 and Co60Fe20B20 thin films were determined using a differential scanning calorimeter (DSC). The thermal properties included the glass transition temperature (Tg), onset crystallization temperature (Tx), and glass-forming ability, which were determined according to these values. Using the Kissinger formula revealed that the activation energy of the Co60Fe20B20 with a thickness of 75 Å is the highest, implying that crystallization was the lowest and the Co60Fe20B20 film showed anticrystallization properties. However, the energy of 75 Å Co40Fe40B20 thin films was the lowest, which is opposite to that of Co60Fe20B20. This observation can be reasonably explained based on the concentration of Co or Fe. Therefore, a thickness of 75 Å is critical