Area-selective deposition of BCl₃ on Si(100) for B-doped δ-layer device fabrication

Atomically-precise, δ-doped structures forming electronic devices in Si can be fabricated using depassivation lithography in a scanning tunneling microscope (STM). Incorporation of dopant atoms from gaseous precursors into lithographic patterns enables metallic wires, and precisely placed single atom qubits for quantum information. We present results on the adsorption and incorporation of B from area-selective deposition of BCl₃ onto the Si(100) surface. We show that BCl₃ readily adsorbs onto Si(100) and is selective to H- and Cl-based resists, which can both be patterned using STM. We explore the effects of annealing temperature on B incorporation and the resulting electrical activation of B δ-layers with peak concentrations >10²⁰ B/cm³. Finally, we perform low-temperature electrical characterizations of B-delta layers and demonstrate fabrication of atomic-scale, B-doped devices.