A little more than a monolayer-thick pureboron (PureB) layer was deposited on silicon at 250 • C by chemical vapor deposition (CVD), forming junctions with low saturation current. They displayed the same efficient suppression of electron injection as PureB diodes fabricated with a few nm-thick PureB layer deposited at 400 • C. Assuming high concentrations of acceptor states at the B-to-Si interface, induced by a fixed negative charge in the range from 5 × 10 13 cm −2 to 5 × 10 14 cm −2 , would be consistent with the experiments and device simulations that exhibit an efficient suppression of electron injection. Metallization of the B-layers was studied, showing that in many situations, thinning of the layer to monolayer thickness will lead to a significant increase in the electron injection.