Formation of ultrashallow <i>p</i>+ layers in silicon by thermal diffusion of boron and by subsequent rapid thermal annealing

Abstract

Boron atoms are incorporated into (100)Si wafers by heating the substrates at 800 °C for 30 min in a (B2H6+H2) atmosphere and by subsequent rapid thermal annealing above 900 °C. Atomic and carrier-concentration profiles of boron-doped layers have been examined by a secondary-ion mass spectrometry and by differential Hall measurements, respectively. Experimental results have clearly shown that ultrashallow p+ layers, 300 Å thick, with a surface carrier concentration of 7.26×1019/cm3 can be formed by diffusion of boron at 800 °C and by subsequent RTA at 100 °C.