One of the key engineering activities to achieve qubits that have the longest coherence times is materials engineering to produce purified substances that will help reduce the impact of things that will degrade the coherence time of a qubit. For spin qubit technologies a key material that is important is the starting silicon wafer upon which the qubit structures are built. Natural Silicon consists of three isotopes including Si-28 (92.2%) which has zero electron spin, Si-29 (4.7%) which has a spin state of 1/2, and Si-30 (3.1%) which has also has zero spin. Natural silicon is perfectly fine for semiconductor processing since transistors are not sensitive to electron spins. But for spin qubits built on silicon wafers, the Si-29 is a problem since the 1/2 spin state will hurt the coherence times.