Electric Conduction in Phosphorus Doped Silicon at Low Temperatures

Abstract

The impurity conduction in phosphorus doped n-type silicon has been investigated at temperatures between 1.1°K and 300°K. The samples ranged in concentration of excess donors from 1.2.10¹⁸ to 2.5.10²⁰cm⁻³. A metallic type impurity conduction and a negative magnetoresistance are observed in samples containing higher than 4.10¹⁸cm⁻³ excess donors. An intermediate type impurity conduction is observed in samples containing from 1.7.10¹⁸ to 4.10¹⁸cm⁻³ excess donors. In metallic samples with donor concentration higher than 6.10¹⁸cm⁻³, the resistivity increases monotonically with temperature T up to the Fermi degeneracy temperature T_D of respective samples according to a simple formula, ρ(T)=ρ(4.2°K)[1+A(T⁄T_D)^B], where A and B are constants.