Characterization of amorphous boron layers as diffusion barrier for pure aluminium

A deposited boron layer is investigated as a diffusion barrier between Al and Si. The doping reaction of diborane B
₂
H
₆
on Si(100) substrates forms an ultra-shallow p
⁺
-doped region and amorphous boron layer, the barrier properties of which are tested at different thicknesses. Experimental data obtained from extensive microscopy analyses are used to asses the topography and chemical properties of the silicon/boron surface when in contact with pure aluminium. In this study it is demonstrated that the normally observed spiking behaviour of Al on Si can be prevented and a perfect, spike- and precipitate-free interface can be achieved.