TRANSPORT-PROPERTIES OF SILICON IMPLANTED WITH BISMUTH

The Hall effect and resistivity of Si:Bi with donor concentration vary ing from 3.0X10(17) to 1.4X10(20) cm(-3) Were measured from room tempe rature down to 13 K. The samples were prepared by Bi+ implantation in Van der Pauw structures delineated in Si chips. The measured resistivi ties were compared with the ones calculated by a generalized Drude app roach at similar temperatures and doping concentration, presenting fai rly good agreement. The critical impurity concentration N-c of the met al-nonmetal transition was measured to be around 2X10(19) cm(-3). The critical concentration N-c was calculated by comparing the ionization energy of the insulating phase with the total energy of the metallic p hase. This value of N-c agreed very well with the one obtained experim entally and the values estimated from other theoretical approaches.