Formation of β-FeSi2 by implanting multicharged iron ions produced in an ECR ion source

Multicharged Fe ions have been produced from solid material which is safe and easy in handling in a 2.45 GHz electron cyclotron resonance (ECR) ion source, and applied to formation of shallow β iron disilicide (β-FeSi2) layer in Si substrate. We produce multicharged Fe ions from pure Fe powder by evaporating method using boron-nitride (BN) crucible in the ECR ion source. Extraction voltage is normally 10 kV. The implanting energy is controlled by selecting the charge state of multicharged ions. After pre-sputtering by Ar+ ion beams, we implant Fe3+-6+ beams to the n-type Si (1 0 0) substrate. Then we carry out post annealing of samples at about 600 °C. The implanted substrates are characterized by X-ray diffraction (XRD) with thin-film optics. Then we succeeded in producing β-FeSi2 layer in the Si substrate. According to the dependence of intensity of XRD spectrum on the incident angle of the X-ray, we could confirm that depth profile was controlled by choosing the charge state of the multicharged Fe ion. Moreover, we confirmed their diode characteristics by measuring current-voltage characteristics.