A self-aligned fabrication process for silicon quantum computer devices

We describe a fabrication process for devices with few quantum bits (qubits), which are suitable for proof-of-principle demonstrations of silicon-based quantum computation. The devices follow the Kane proposal of using the nuclear spins of P-31 donors in Si-28 as qubits, controlled by metal surface gates and measured using single-electron transistors (SETs). The of accurate registration P-31 donors to control gates and read-out SETs is achieved through the use of a self-aligned process which incorporates electron beam patterning, ion implantation and triple-angle shadow-mask metal evaporation.