Improvement of the electrical properties of beta-FeSi2 films on Si (001) by high-temperature annealing

The crystal quality, mobility and carrier density of the continuous and [10 0]-oriented nondoped beta-FeSi2 films prepared from Si/Fe multilayers on Si (001) substrates using templates were improved by high-temperature anneali ng, in particular, at 900 degrees C. All the annealed samples exhibited n-t ype conduction. The maximum electron mobility of beta-FeSi2 indicated 6900 cm(2)/V.s (46 K) after annealing at 900 degrees C for 42 h. This mobility i s about 15 times higher than that reported so far for nondoped n-type beta- FeSi2. The electron density at room temperature decreased from 2 x 10(20) c m(-3) to 3 x 10(18) cm-3 after the annealing.