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

Abstract

Multicharged Fe ions have been produced from solid material which is safe and easy in handling in a 2.45GHz 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 10kV. 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 (100) 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.